Abstract
Abstract: A multigene phylogenetic assessment of North American species of Mallocybe is presented based on analyses of rpb1, rpb2, ITS, and 28S rDNA nucleotide data. This framework enables a systematic revision of the genus for 16 eastern North American species and captures taxonomic and phylogenetic diversity in a global context. A grade of two unusual and poorly known North American species stems from the most recent common ancestor of the genus that gives rise to three core subgroups named here as clades Unicolores, Nothosperma, and Mallocybe. The grade of taxa includes the poorly known Lepista praevillosa from Florida and a new species from the southern Appalachians, M. montana, both of which appear to be narrow-range endemics. Clade Nothosperma is characterized by Australian and New Zealand species, whereas clade Unicolores is composed of six species from eastern North America and East Asia. Clade Mallocybe is dominated by numerous north temperate taxa and constitutes the sister group to clade Nothosperma. These major clades are distinguished by a combination of phylogeny, morphology, geographic distribution, and ecology. In addition, four North American species are described as new: M. leucothrix, M. luteobasis, M. montana, and M. tomentella. Several names originating in North America, long ignored or misunderstood in the literature, are revitalized and established by type comparisons and modern reference material collected from or near type localities. In addition, 11 species were subjected to mass spectrometry muscarine assays, none of which contained detectable amounts of muscarine except for two: M. sabulosa and M. praevillosa. This confirms a diffuse phylogenetic distribution of muscarine within the genus. Taxonomic descriptions are presented for 16 species, several synonymies proposed, and four new combinations made. A key to species of eastern North American Mallocybe is presented, along with illustrations of important diagnostic features.
Citation: Matheny PB, Kudzma LV, Graddy MG, Mardini SM, Noffsinger CR, Swenie RA, Walker NC, Campagna SR, Halling R, Lebeuf R, Kuo M, Lewis DP, Smith ME, Tabassum M, Trudell SA, Vauras J (2023). A phylogeny for North American Mallocybe (Inocybaceae) and taxonomic revision of eastern North American taxa. Fungal Systematics and Evolution 12: 153–201. doi: 10.3114/fuse.2023.12.09
Keywords: Agaricales, fungi, new taxa, secondary metabolites, systematics
INTRODUCTION
The genus Mallocybe, one of seven genera of Inocybaceae, was recently elevated to generic rank by Matheny et al. (2020). Species of Mallocybe are distinguished from other genera of Inocybaceae by a combination of the presence of necropigmented basida (basidia that collapse and fill with ochraceus or brownish yellow pigment), smooth basidiospores, a typically dark reaction to alkali solutions on the pileus surface, non-reddening context; cheilocystidia arising as terminal elements of hymenophoral trama that are, in most species, less than 50 µm long; and the absence of pleurocystidia. Previous work has shown that the toxin muscarine is present in some species but not detectable in others (Kosentka et al. 2013).
In the field many species of Mallocybe typically feature adnate or subdecurrent lamellae, a squamulose or tomentose pileus surface, and a short stipe relative to the width of the pileus. Coloration of most species is typically some shade of
brown, yellowish brown, or brownish yellow. However, several exceptions to this suite of features have been noted (e.g., Cripps et al. 2010, Matheny & Bougher 2017). The genus is a strongly supported monophyletic group and is widely distributed across the globe occurring in Africa, Asia, Australia, Europe, New Guinea, New Zealand, and North America (Matheny et al. 2020). New species of Mallocybe continue to be described from Africa, Asia, and Europe (Crous et al. 2020, Saba & Khalid 2020, Aignon et al. 2021, Mao et al. 2022, Hu et al. 2023), and new combinations continue to be made into the genus (Saba et al. 2020) raising the number of species to about 65 worldwide. Mallocybe is most diverse at temperate latitudes forming ectomycorrhizal associations with a number of different plant families (e.g., Daskalopoulos et al. 2021), and some species are important constituents of alpine and arctic systems (Favre 1955, Kühner 1988, Cripps et al. 2010). A few species have been described or documented from the Old-World tropics (Horak 1980, Matheny et al. 2009, Horak et al. 2015, Matheny & Bougher 2017, Aignon et al. 2021), but none have yet been described from the Neotropics and southern South America.
European Mallocybe have generally been recognized as a small group containing anywhere from 5 to 25 species. An early attempt to classify species attributable to Mallocybe was done by Heim (1931), who proposed “Stirpe dulcamara” in Inocybe sect. Dulcamarae. The stirps contained five species. Singer (1986) placed European species of Mallocybe in Inocybe sect. Depauperatae typified by Inocybe delecta and recognized five species in the group. Alessio & Rebaudengo (1980) treated 12 taxa, including several infraspecific varieties and forms.
Kuyper (1986) established Inocybe subg. Mallocybe in the sense used here but did not include a taxonomic treatment for the ten estimated species he accepted at that time from the northern hemisphere. Kühner (1988) described ten new species in Inocybe sect. Dulcamarae from alpine zones in central Europe, which doubled the number of known species in the group. Stangl (1989) recognized eight species in Inocybe subg. Mallocybe from central Europe, and Kobayashi (2002) recognized five including consideration of samples from East Asia. Jacobbson & Larsson (2012) treated 14 species of Inocybe subg. Mallocybe in northern Europe. Bon (1997), however, referenced 31 taxa (among 23 species) in his keys, and Ludwig (2017) recognized 25. In North America no extensive revision has been made of species of Mallocybe, but Cripps et al. (2010) documented six intercontinental Euro-American species from arctic-alpine settings in western North America. Bessette & Fatto (1998) attributed a new species they described from New York, I. angustispora (see also Bessette et al. 2001), to an alliance with what would be recognized as Mallocybe today. However, Matheny & Ammirati (2003) showed that I. angustispora was a later synonym of Cortinarius aureifolius, an atypically smooth-spored species of Cortinarius. A few new taxa were documented or described from the Old-World tropics as cited above, and Matheny & Bougher (2017) added five new species to Inocybe subgenus Mallocybe from Australian temperate and tropical regions. Horak (2018) included a description of a new species, I. callichroa, from New Zealand, which superficially resembles other species of Mallocybe. Lastly, five new species were recently described from China (Mao et al. 2022, Hu et al. 2023). Globally, about 65 species of Mallocybe can now be recognized since Matheny (2009) initially estimated ca. 30 species worldwide in the group.
Mallocybe has long been recovered as a single clade based on molecular phylogenetic analyses. Matheny (2005) sampled 12 species-level lineages of Inocybe subg. Mallocybe based on phylogenetic analyses of three gene regions, and Matheny et al. (2009) followed up on that study by including 25 species of Inocybe subg. Mallocybe worldwide. Cripps et al. (2010) reconstructed an rDNA phylogeny that sampled 13 species-level lineages of Inocybe subg. Mallocybe, and Ryberg et al. (2010) included about a dozen lineages based on analyses of nuclear and mitochondrial rDNA. All these treatments recovered Mallocybe as a strongly supported monophyletic group. However, Bandini et al. (2018) recently excluded Inocybe stenospora from Mallocybe, where it had been previously proposed (Stangl 1986), based on molecular phylogenetic evidence. Unfortunately, phylogenetic studies have varied on identification of the sister group to Mallocybe and have lacked strong evidence in favor of any sister group arrangement (Matheny 2005, Matheny et al. 2009, 2012, 2020, Alvarado et al. 2010, Ryberg et al. 2010). Auritella, Tubariomyces, and Inosperma, or some configuration of these taxa, have all been recovered as potential sister groups to Mallocybe but without strong support. In addition, no prior works have proposed any infrageneric molecular systematic treatment, although Hu et al. (2023) recovered three major clades within the genus (identified as clades A, B, and C) with an infrageneric multigene phylogeny based on combined analysis of ITS, 28S, and rpb2 sequences.
Our objectives here are to: (1) present a global molecular phylogenetic assessment of Mallocybe based on rpb1, rpb2, ITS, and 28S data; (2) focus on identification of major lineages within Mallocybe incorporating North American taxa; (3) assay relative abundance of muscarine in North American samples; and (4) revise and document species that occur in eastern North America relative to those elsewhere. In addition, we also highlight the uniqueness of several lineages documented from western North America. To stabilize application of names based on old or poorly preserved type collections, we collected fresh specimens at or near type localities of species attributable to Mallocybe described by Peck, Murrill, and others in New York and Florida. Taxonomic descriptions of 16 species of Mallocybe from eastern North America are presented, including description of four new species, clade designations within the genus, a taxonomic key, and illustrations of diagnostic microscopic features and photographs of basidiomes. The work also provides a framework to revise Mallocybe species from western North America and elsewhere in the future.
MATERIALS AND METHODS
Morphology
Notes on fresh samples from the field were aided by reference to the color guides Munsell Soil Color Chart (1954) [e.g., 10YR 7/4), Ridgway (1912) [e.g., Dresden Brown], and Kornerup & Wanscher (1967) [e.g., 6E8]. “L” refers to the number of lamellae that reach the stipe. PDAB or p-dimethylaminobenzaldehyde (Matheny et al. 2013) and 5 % KOH (Kuyper 1986) were used to induce any microchemical reactions. After observation, fresh specimens were air-dried in a food dehydrator. Collections were accessioned at the Herbarium of the University of Tennessee (TENN) and the University of Washington Herbarium (WTU) or maintained in the private herbarium of L.V. Kudzma. Loans of specimens were obtained from the Royal Botanic Garden Edinburgh (E), the Fungarium of the Florida Museum of Natural History (FLAS), the Herbarium of the University of Helsinki (H), the New York Botanical Garden (NY), and WTU. Herbarium codes follow Thiers [continuously updated]. Hand sections made with a razor and lamellar fragments were mounted in 5 % KOH to examine anatomical features such as the pileipellis, cheilocystidia, basidia, and basidiospore morphology and size (terminology following Kuyper 1986). Observations and measurements were made with a Nikon i80 Eclipse light microscope and Elements D software (Nikon Instruments Inc, Melville, New York). Outlier measurements constituting < 5 % of observations are indicated in parentheses, and mean values are italicized. Q-values are ratios of spore length to spore width and were calculated for each spore and then averaged. The total number of spores measured (x) and the number of specimens sampled (y) are indicated as x/y. Type collections were examined from FLAS, H, NY, TENN, and WTU.
DNA extractions and sequencing
Between 20 and 30 mg of dried pileal fragments were ground with liquid N and a pinch of sterile sand. In most cases, procedures for DNA extraction followed Judge et al. (2010) or Matheny et al. (2002). Recently collected samples underwent a rapid alkaline DNA extraction and PCR amplification as described by Matheny & Swenie (2018). ITS amplicons were amplified and sequenced using primers ITS1F and ITS4 (White et al. 1990). 28S amplicons were amplified using LR0R and LR7 and sequenced with these primers and LR5 (Vilgalys & Hesler 1990, Cubeta et al. 1991). The most variable region of rpb1 was sequenced between conserved domains A and C using primers gAf (Stiller & Hall 1997) and fCr (Matheny et al. 2002). Both primers were used for sequencing along with internal primers int2F, int2.1F, and int2.1R (Frøslev et al. 2005). The most variable region of rpb2 was amplified and sequenced between conserved domains 6 and 7 using primers b6F and b7.1R (Matheny 2005). For materials gathered in New Jersey, PCR procedures and sequencing followed Matheny & Kudzma (2019). For materials older than 30 years, the ITS spacers were amplified and sequenced separately following Sánchez-Garcia et al. (2014). Chromatograms were constructed and edited in Sequencer v. 5.0.1 (Gene Codes Corp., Ann Arbor, Michigan). New sequences were submitted to GenBank and are shown in bold font in Table 1.
Table 1.
SSpecimen data and DNA sequences analyzed for this study. New DNA sequences are in bold.
| Species | Specimen-voucher (Herbarium) | Geographic origin | Ecology | GenBank Accession Numbers | |||
|---|---|---|---|---|---|---|---|
| ITS | 28S | rpb1 | rpb2 | ||||
| M. africana | 96012(PC0088767) | Zambia | Miombo woodland | MN178510 | MN178542 | — | — |
| 96204(PC0088756) | Zambia | Miombo woodland | MN178511 | EU56987l | — | — | |
| M. agardhii | EL88–04 (GB) | Sweden | Salix, calcareous | FJ904123 | FJ904123 | — | — |
| JV7485F (WTU) | Finland | Betula, Quercus, gravel | — | AY380365 | AY351792 | AY333772 | |
| JV13740 (WTU) | Finland | Salix, Betula, wet depression | — | AY380366 | AY337362 | AY337362 | |
| AB980912 (GB) | Denmark | Salix | HM209790 | HM209790 | — | — | |
| M. arenaria | EL250–08 (GB) | France | — | FN550937 | FN550937 | — | — |
| M. arthrocystis | BJ900815 (GB) | Sweden | Salix | — | GU980655 | — | — |
| CLC1141 (MONT) | Colorado | Salix | GU980653 | GU980653 | — | — | |
| CLC1356 (MONT) | Colorado | Salix | GU980649 | GU980649 | — | — | |
| CLC1357 (MONT) | Colorado | Salix | — | GU980652 | — | — | |
| CLC1688 (MONT) | Colorado | Salix | GU980651 | GU980651 | — | — | |
| CLC1752 (MONT) | Colorado | Salix | GU980650 | GU980650 | — | — | |
| EL62–07 (GB) | Sweden | Salix | FN550941 | FN550941 | — | — | |
| PBM2397 (WTU) | Norway | Picea, Betula, Salix, eutrophic spruce forest | — | AY380394 | AY351817 | AY337402 | |
| SJ06–011 | Sweden | Salix | GU980654 | GU980654 | — | — | |
| M. aurantiidisca | 2020ZD01 (MHKMU) | Zhejiang | Mixed broad-leaved | OM179937 | — | — | — |
| NJ3109 (MHKMU) | Zhejiang | Fagaceae dominant | OM179935 | OM138834 | — | OM83575l | |
| NJ3396 (MHKMU, holotype) | Zhejiang | Pinus dominant | OM179936 | OM138835 | — | OM835752 | |
| M. crassivelata | AH29788 | Spain | Castanea forest | MN536810 | — | — | — |
| AH46622 | Spain | Quercus, Pinus | MN5368ll | — | — | — | |
| MCVE21499 | Italy | Picea forest | MN536813 | — | — | — | |
| MCVE 29561 (holotype) | Slovenia | Fagus | MN536812 | MN537138 | — | — | |
| M. delecta | JV21393 | Finland | Pinus, Betula, Salix, Quercus | OQ448534 | OQ448534 | — | — |
| P. Karsten 1636 (H, holotype) | Finland | — | OQ448533 | — | — | — | |
| M. depressa | FM1300 (BJTC) | Shanxi | Pinus dominant | OM801895 | OM801900 | — | OM780099 |
| FM1695 (BJTC, holotype) | Shanxi | Pinus dominant | OM801899 | OM80904 | — | OM780ЮO | |
| M. errata | DED8022 (SFSU; ZT13034) | Thailand | Pinus, Dipterocarpus | EU569844 | EU569844 | — | — |
| ZT9238 | Thailand | Pinus, Dipterocarpus | — | EU569845 | — | — | |
| ZT10108 (type) | Thailand | Pinus | — | GQ892935 | — | — | |
| M. fibrillosa (=I dulcamara | CLC1131 (MONT) | Montana | Salix | GU980639 | GU980639 | — | — |
| sensu Cripps et al. 2010) | CLC1160 (MONT) | Montana | Salix | GU980642 | |||
| CLC1241 (MONT) | Colorado | Salix | GU980637 | GU980637 | — | — | |
| CLC1295 (MONT) | Colorado | Salix | GU980636 | GU980636 | — | — | |
| CLC1333 (MONT) | Colorado | Salix | GU980635 | GU980635 | — | — | |
| CLC1364 (MONT) | Colorado | Salix | GU980641 | — | — | — | |
| CLC1408 (MONT) | Colorado | Salix | GU980647 | GU980647 | — | — | |
| CLC1421 (MONT) | Colorado | Salix | GU980646 | GU980646 | — | — | |
| CLC1458 (MONT) | Colorado | Salix7 | GU980638 | GU980638 | — | — | |
| CLC1581 (MONT) | Wyoming | Salix | GU980634 | GU980634 | — | — | |
| CLC1664 (MONT) | Colorado | Dryas? | GU 980640 | GU 980640 | — | — | |
| CLC1841 (MONT) | Colorado | Salix | GU 980644 | GU 980644 | — | — | |
| EL33–05 (GB) | Norway | Salix | GU980645 | GU980645 | — | — | |
| EL59–05 (GB) | Norway | Betula | GU980643 | GU980643 | — | — | |
| LVK14371 | Maine | Mixed woods | MN178498 | MN178526 | MN203504 | MN203517 | |
| LVK14390 | Maine | — | MN178499 | MN178527 | — | MN203518 | |
| LVK15242 | Maine | Picea, Betula | MN178500 | — | — | — | |
| LVK22085 | Maine | Mixed woods | OP917925 | OP918013 | — | — | |
| PBM2350 (WTU) | Washington | Conifers | — | EU600834 | EU600832 | EU600833 | |
| REH10168 (TENN-F-073177) | New York | Abies, Picea, Betula, Thuja, Pinus | MH024850 | MH024886 | MK415442 | MH577503 | |
| 2030506–001 (UBC F19167 as /. gymnocarpa) | British Columbia | — | HQ604785 | HQ604785 | — | — | |
| M. fulviceps | DPL13914 (TENN-F-076539) | Louisiana | Quercus nigra | OQ707213 | — | — | — |
| MES–3773 (FLAS-F-66615) | Florida | Quercus, karst | MZ404927 | — | — | — | |
| MES–2993 (FLAS-F-66574) | Florida | Quercus, karst | MT415969 | — | — | — | |
| PBM4533 (TENN-F-075556) | Florida | Quercus, Pinus, karst | MZ404928 | MZ375430 | — | — | |
| PBM4542 (TENN-F-75565) | Florida | Pinus, Quercus, karst | MZ404929 | MZ37543l | MZ404598 | MZ405010 | |
| PBM4715 (TENN–F-F077389) | Florida | Pinus, Quercus, karst | OQ208757 | — | — | — | |
| PBM4718 (TENN-F-077392) | Florida | Pinus, Quercus, karst | OQ208758 | — | — | — | |
| PBM4722 (TENN-F-077396) | Florida | Pinus, Quercus, karst | OQ208759 | — | — | — | |
| PBM4726 (TENN-F-077450) | Florida | Car pinus, Quercus, karst | OQ208760 | — | — | — | |
| M. fulvipes (subclade B sensu Cripps et ai. 2010) | CLC1490 (MONT) | Colorado | Salix | GU980612 | — | — | — |
| CLC1566 (MONT) | Wyoming | Salix | GU980606 | GU980606 | — | — | |
| CLC1580 (MONT) | Wyoming | Salix | GU980608 | GU980608 | — | — | |
| CLC1844 (MONT) | Colorado | Salix | GU980611 | GU980611 | — | — | |
| EL83–07 (GB) | Sweden | Salix | FN550935 | FN550935 | — | — | |
| SJ84030 (GB - same field no. as /. granulosa) | Sweden | Salix | GU980609 | GU980609 | — | — | |
| M. fuscomarginata | BJ890718 (GB) | Sweden | Salix | GU980656 | GU980656 | — | — |
| EL109–06 (GB) | Sweden | Salix | FN550940 | FN550940 | — | — | |
| EL77–07 (GB) | Sweden | Dryas | GU980657 | GU980657 | — | — | |
| M. granulosa | EL138–09 (GB, type) | Sweden | Salix, likely calcareous ground | KR029727 | KR029727 | — | — |
| Kuhner70–147 (as/. squarrosoannulata) | — | — | GU980610 | GU980610 | — | — | |
| SJ11008 | Sweden | Salix | KR029726 | KR029726 | — | — | |
| SJ12916 | Norway | — | KR029728 | KR029728 | — | — | |
| SJ12017 | Norway | Salix | KR029729 | KR029729 | — | — | |
| SJ84030 (as 1. squarrosoannulata) | Sweden | Salix | KR029725 | KR029725 | — | — | |
| M. gymnocarpa | SJ980707 (GB) | Sweden | — | AM882866 | AM882866 | — | — |
| 16413 | Italy | — | JF908161 | — | — | — | |
| EL78–04 (GB; as “dulcamara”) | Sweden | — | AM882865 | — | — | — | |
| M. heimii | JV14932 (WTU) | Italy | Pinus, sandy soil | — | AY380379 | AY351804 | AY337380 |
| G0256 (NL–0874) | Hungary | — | — | MK27823l | — | — | |
| M. isabellina | NLB420(PERTH 08072442) | Western Australia | Eucalyptus, lawn | KP171139 | KP170917 | MN203505 | KJ811583 |
| NLB836 (PERTH 08318441) | Western Australia | Agonis, Spyridium, Acacia, Melalecua, heath- scrub | KP171141 | KP170920 | MN203506 | KJ811586 | |
| E8290 (PERTH 07699255, type) | Western Australia | Eucalyptus, lawn | KP171137 | KP170915 | — | KJ811581 | |
| NLB405(PERTH 08096635) | Western Australia | Grassy parkland | KP171138 | KP170916 | — | KJ811582 | |
| PBM3610 (PERTH 08319766) | Western Australia | Eucalyptus, Corymbia, Jarrah-Marri forest | — | KP170919 | — | KJ811585 | |
| E3730(PERTH 07712758) | Western Australia | Sand dunes | MN178501 | MN178528 | — | MH618212 | |
| NLB836 (PERTH 08318441) | Western Australia | Agonis, Spyridium, Acacia, Melaleuca, heath- scrub | KP171141 | KP170920 | — | KJ811586 | |
| NLB800 (PERTH 08318832) | Western Australia | Eucalyptus, Corymbia, burned Jarrah-Marri forest | KP171140 | KP170918 | — | KJ811584 | |
| M. isabellina aff. | NLB49l (PERTH 08073287) | Western Australia | Eucalyptus, parkland | KP171142 | KP170921 | — | KJ811587 |
| PBM2207 ⁄ E7056 (TENN-F-066822) | Western Australia | Corymbia, lawn | — | AY380381 | AY351806 | AY337382 | |
| PBM3595 (TENN-F-066498) | Western Australia | Eucalyptus, Corymbia, burned Jarrah-Marri forest | KP171143 | KP170922 | — | KP170922 | |
| M. latifolia | Nr. 3908 (M–0216716), EL3 (type M. acystidiata) | Germany | Picea, calcareous | OR139041 | — | — | — |
| Isolate 136 | Shaanxi | Populus simonsii ECM root | LC013759 | — | — | — | |
| Isolate 1969 | Shaanxi | Populus simonsii ECM root | LC013761 | — | — | — | |
| LVK22088 | Maine | Mixed woods | OP918037 | OP918067 | OQ870543 | — | |
| LVK22089 | Maine | Mixed woods | OP918038 | — | OQ870544 | OP924514 | |
| M0364156 | Arizona | Populus, Cypress | MN177633 | — | — | — | |
| M–0216738 (type M. latifolia) | Germany | Betula, Picea, calcareous | OQ976965 | — | — | — | |
| PBM4535 (TENN-F-075558) | Florida | Pinus, Quercus | MZ404930 | MZ375432 | MZ404599 | — | |
| PBM4537 (TENN-F-075560) | Florida | Quercus, Pinus, Carpinus | MZ404931 | MZ375433 | MZ404600 | MZ405011 | |
| M. latispora | EL212–06 (GB) | France | — | FN550938 | FN550938 | — | — |
| Species | Specimen-voucher (Herbarium) | Geographic origin | Ecology | ITS | GenBank Accession Numbers 28S rpb1 | rpb2 | |
| EL190–08 (GB) | Sweden | — | KR029724 | KR029724 | — | — | |
| EL3–04 (GB) | Sweden | — | AM882859 | — | — | — | |
| JV19684 (TENN-F-074801) | Finland | Populus, Salix, Pinus seedlings, on calcareous mull | MN178502 | — | — | MN203519 | |
| JV19640F (TENN-F-063757) | Finland | Salix, Betul¤, Pinus, Populus, Pice a, calcareous soil | MN178503 | MN178529 | — | MN203520 | |
| JV19642F (TENN-F-063523) | Finland | Salix, Betula, Pinus, Populus, Pice a, calcareous soil | MN178504 | MN178530 | — | MN203521 | |
| JV19650F (TENN-F-063759) | Finland | Pinus, Betula, Picea, Salix, near limestone quarry | MN178505 | MN178531 | MZ404601 | MN203522 | |
| STU–F–0901665 (type M. plebeia) | Germany | Salix, Pinus, calcareous soil | ONO03442 | — | — | — | |
| M. leucoblema | CLC1721 (MONT) | Colorado | Dryas | GU980632 | GU980632 | — | — |
| EL66–08 (GB) | Sweden | — | FN550936 | FN550936 | — | — | |
| EM29 | Russia | Epipogium aphyllum root | — | EU711227 | — | — | |
| JV16437 (WTU) | Finland | Pinus, Picea, Salix, Betula, Populus, calcareous soil | — | EU569858 | AH013036 | AY333310 | |
| JV2898 | Finland | Picea, Betula | HM209789 | HM209789 | — | — | |
| Moser 71123 (TENN-F-037075) | France | — | FJ601811 & FJ601812 | MN178532 | — | — | |
| PBM1522 (WTU) | Wyoming | Picea, Abies, calcareous soil | — | MN178533 | — | MH5775ll | |
| PBM2737 (TENN-F-062549) | Colorado | Picea | HQ23248l | MN178534 | MN203507 | — | |
| SEB97–09 (GB) | Sweden | Pinus | GU980631 | GU980631 | — | — | |
| SM2324(GB) | Sweden | Picea | GU980630 | GU980630 | — | — | |
| TAA128324 (GB) | Estonia | Salix | GU980633 | GU980633 | — | — | |
| M. leucoloma | CLC1232 (MONT) | Colorado | Salix | GU980624 | GU980624 | — | — |
| CLC1355 (MONT) | Colorado | Salix | GU980623 | GU980623 | — | — | |
| CLC1431 (MONT) | Colorado | Salix | GU980619 | GU980619 | — | — | |
| CLC1442 (MONT) | Colorado | Salix | GU980620 | GU980620 | — | — | |
| CLC1703 (MONT) | Colorado | Salix | GU980617 | GU980617 | — | — | |
| CLC1869 (MONT) | Colorado | Salix | GU980618 | GU980618 | — | — | |
| CLC1877 (MONT) | Colorado | Salix | GU980621 | GU980621 | — | — | |
| EL40–07 (GB) | Sweden | Salix | GU980615 | GU980615 | — | — | |
| EL41–07 (GB) | Sweden | Salix | GU980615 | GU980615 | — | — | |
| EL50–05 (GB) | Norway | Dryas, Salix | AM882855 | AM882855 | — | — | |
| EL106–07 (GB) | Sweden | Salix | GU980627 | GU980627 | — | — | |
| EL107–07 (GB) | Sweden | Salix | GU980625 | GU980625 | — | — | |
| EL1–06(GB) | Norway | Salix | GU980626 | GU980626 | — | — | |
| EL69–05 (GB) | Norway | Dryas, Salix | GU980616 | GU980616 | — | — | |
| Species | Specimen-voucher (Herbarium) | Geographic origin | Ecology | ITS | GenBank Accession Numbers 28S rpb1 | rpb2 | |
| Kühner 63–36 (G, type) | France | Dryas, Salix | GU980614 | GU980614 | — | — | |
| PBM1574 (WTU) | Wyoming | Salix | — | EU555458 | — | — | |
| PBM2296 (WTU) | Washington | Conifers mixed with Betula, Populus | — | AY380372 | AY351798 | AY337373 | |
| M. leucothrixsp. nov. | iNat131154234 (sp-AZOl) | Arizona | Pinus, Quercus, Juniperus, calcareous soil | OP784362 | — | — | — |
| iNat131155272 (sp-AZOl) | Arizona | Pinus, Quercus, Juniperus, calcareous soil | OP784312 | — | — | — | |
| iNat131844666 (sp-AZOl) | Arizona | Pinus, Quercus, Juniperus, calcareous soil | OP784364 | — | — | — | |
| PBM454l (TENN-F-075564, type) | Florida | Quercus, Pinus, karst topography | MZ404932 | MZ375434 | MZ404602 | MZ405012 | |
| PBM453l (TENN-F-075554) | Florida | Quercus, Pinus, karst topography | MZ404933 | MZ375435 | MZ404603 | MZ405013 | |
| M. longicystis | FYG637l (MHKMU) | Hainan | Fagaceous trees | OM179926 | OM135609 | — | OM835746 |
| FYG6373 (MHKMU) | Hainan | Fagaceous trees | OM179927 | OM135610 | — | OM747850 | |
| FYG6374 (MHKMU, type) | Hainan | Fagaceous trees | OM179928 | OM135611 | — | OM835747 | |
| FYG6376 | Hainan | Fagaceous trees | OM179929 | OM135612 | — | OM835745 | |
| M. luteobasis sp. nov. | MK06071503 (TENN-F-073751) | Illinois | Carya, Juniperus | MN178506 | MN178535 | MN203508 | MN203523 |
| MK06211102 (TENN-F-073749) | Illinois | Quercus, Carya | MT239045 | — | — | — | |
| MK07140307 (TENN-F-073752) | Indiana | Deciduous woods | MN178507 | MN178536 | MZ404604 | MN203524 | |
| MK07180705 (TENN-F-073750, type) | Illinois | Quercus | MN165953 | MN178537 | MZ404605 | MN203525 | |
| Sayers s.n. (TENN-F-063525) | Kansas | Quercus | — | JN975028 | — | MH577502 | |
| M. malenconii | EL807 | Spain | — | FN550939 | FN550939 | — | — |
| HMAS 262707 | China | — | KJ810603 | — | — | — | |
| IK–00018 | Poland | — | KX602259 | — | — | — | |
| JV4470F (WTU) | Finland | Pinus sylvestris, sandy soil | — | GQ906704 | — | MN203526 | |
| JV5498A (WTU) | Finland | — | — | EU569870 | — | EU569869 | |
| JV5824F (WTU) | Finland | Picea, Betula, Salix, sandy soil | — | MN178538 | — | — | |
| JV23101 (WTU) | Finland | Betula, Salix, Picea | HM209787 | HM209787 | — | — | |
| LVK21286 | New York | Mixed conifers and hardwoods | OP04639l | OP046370 | — | OP060362 | |
| LVK22039 | Maine | Quercus, Pinus | OP918252 | — | — | — | |
| LVK22045 | Maine | Quercus, Pinus | OP913409 | — | — | — | |
| PAM98941302 | France | Betula, Pinus | HM209788 | HM209788 | — | — | |
| SJO30822 (GB) | Sweden | Pinus | AM882862 | — | — | — | |
| 2020521–001 (UBC F19123) | British Columbia | — | HQ604776 | HQ604776 | — | — | |
| M. montana sp. nov. | PBM3872 (TENN-F-067500, type) | North Carolina | Riverine hardwood forest | OP046392 | OP04637l | OQ866119 | OP060363 |
| PBM4190 (TENN-F-074532) | North Carolina | Pinus, Betula | MN178512 | — | — | — | |
| PBM4614 (TENN-F-075781) | North Carolina | Tsuga, Pinus, Quercus, Betula | OP046393 | OP046372 | OP060357 & OP060358 | OP060364 | |
| M. multispora | C04248 (CSU) | Oklahoma | Quercus, Carya, Ulmus, Fraxinus, sand | MN178509 | MN178540 | MZ404606 | — |
| DPL13518 (TENN-F-077876) | Texas | Bottomland hardwood forest near Pinus | OQ707215 | — | — | — | |
| iNat126273738 | Florida | Quercus, Pinus, sandy soil, karst | OP101166 | — | — | — | |
| iNat131720866 | Arizona | Pinus, Quercus, Juniperus, calcareous | OQ023952 | — | — | — | |
| FLAS-F-66616 | Florida | Quercus, karst | MZ404934 | — | — | — | |
| FLAS-F-61779 | Florida | Pinus, Sabal, sandy pine flatlands | MH281884 | MH620328 | — | — | |
| FLAS-F-70016 | Florida | — | OP580228 | — | — | — | |
| MycoMap 10129 | Indiana | hardwoods | OM473595 | — | — | — | |
| MycoMap 10246 | Indiana | Pinus, Quercus | OM473596 | — | — | — | |
| PBM4717 (TENN-F-077391) | Florida | Pinus, Quercus, karst | OQ20876l | — | — | — | |
| M. myriadophylla | IK–00039 | Poland | — | KX602263 | — | — | — |
| JV19652F (TENN-F-063760 - AFTOL- ID 482) | Finland | Pinus, Betula, Picea, Salix, calcareous mull soil | DQ221106 | AY700196 | DQ447917 | AY803751 | |
| JV19678 (TENN-F-063761, type) | Finland | Pinus, Picea, Salix, Betula, Populus | HM209793 | HM209793 | — | — | |
| JV5968F (WTU) | Finland | Betula, Picea, Pinus, calcareous ground | HM209794 | HM209794 | — | — | |
| SZ01 | Germany | — | MF807958 | — | — | — | |
| M. nuptial is | STU–F–0901660 | Austria | Salix, Juniperus, Dryas, Pinus, Alnus | ONO03443 | — | — | — |
| STU–F–0901661 (type) | Austria | Salix | ONO03444 | ONO03444 | — | — | |
| STU–F–0901662 | Germany | Salix | ONO03445 | — | — | — | |
| M. pallidipes | FYG3736 (MHKMU, type) | Jilin | Populus | OM179924 | OM137052 | — | OM835749 |
| FYG3727 (MHKMU) | Jilin | Populus | OM179925 | — | — | OM835750 | |
| M. piceae | FM555 (BJTC, type) | Shanxi | Picea | OM801896 | OM801901 | — | OM780096 |
| FM569 (BJTC) | Shanxi | Picea | OM801897 | OM801903 | — | OM780097 | |
| FM896 (BJTC) | Shanxi | Picea | OM802898 | OM801902 | — | OM780098 | |
| M. praevillosa comb. nov. | FLAS-F-61523 | Florida | Pinus, Quercus | MH211949 & OP046394 | MH620294 & OP046373 | OP060359 | OP060365 |
| PBM4724 (TENN-F-077398) | Florida | Quercus, Pinus, karst | OQ208762 | — | — | — | |
| M. pygmaea | EL48–05 (GB) | Norway | Dryas, Salix | GU980628 | GU980628 | — | — |
| J. Favre (type) | Switzerland | Salix | GU980629 | — | — | — | |
| M. pyrrhopoda | MDB F292/10 (PERTH 08383278) | Western Australia | Antidesma, Glochidion, Melaleuca, Eucalyptus, tropical forest | KP308814 | KP170984 | — | KM406224 |
| MDB F18s/13 (PERTH 08557764) | Western Australia | Melaleuca, tropical | KP308815 | KP170986 | — | KM406226 | |
| PBM3759 (TENN-F-066987, type) | Queensland | Melaleuca, Ĺophostemon, Corymbia, tropical swamp | KP308813 | KP170983 | MN203509 | KM406223 | |
| PBM3740 (TENN-F-066972) | Queensland | Corymbia, Eucalyptus, tropical woodland | — | KP170985 | — | KM406225 | |
| REH9670 | Queensland | Eucalyptus, subtropical | KP641622 | KP171077 | — | — | |
| M. sabulosa | NLB986 (PERTH 08383308) | Western Australia | Corymbia, Acacia, gray sand limestone | — | KP170998 | MN203510 | KM406238 |
| NLB901 (PERTH 08320292) | Western Australia | Acacia, Templetonia, Eucalyptus, shrubland | KP308825 | KP170997 | — | KM406237 | |
| E8178(PERTH 07680732) | Western Australia | Eucalyptus, Corymbia, woodland | KP308822 | JN974916 | — | KM406235 | |
| E8182 (PERTH 07680775) | Western Australia | Eucalyptus, suburban bushland | KP308823 | KP170995 | — | KM406236 | |
| NLB898 (PERTH 08320322, type) | Western Australia | Eucalyptus (planted) | KP308821 | KP170994 | — | KM406234 | |
| MDB F7/ll (PERTH 08383057) | Western Australia | Corymbia, Albizzia, tropical woodland | KP308824 | KP170996 | — | — | |
| Mallocybe sp. 1 | uncultured | Alaska | Dryas | JX630703 | — | — | — |
| — | Alaska | Dryas | JX630716 | — | — | — | |
| — | Alaska | Dryas | JX630710 | — | — | — | |
| Mallocybe sp. 2 (=/. | BK06069724 (WTU) | Oregon | Conifers | — | AY380400 | AY351825 | MH577505 |
| marmoripes sensu N. Am. auct., non G.F. Atk.) | BK06069725 (WTU) | Oregon | Conifers | MN178541 | |||
| LLN93063018 (WTU) | Washington | Pinus, Salix, Alnus | OQ734476 | — | — | — | |
| 2070626 (UBC F19439 as /. | British Columbia | — | HQ604786 | HQ604786 | — | — | |
| Mallocybe sp. 3 | malenconii van megalospora) PBM1615 | Washington | Picea, Pseudotsuga | AY038327 | AF389549 | AY337374 | |
| Mallocybe sp. 4 | PBM2290 (WTU) | Washington | Conifers | — | EU555446 | — | EU555445 |
| Mallocybe sp. 5 | JFA13285 (WTU) | Washington | Picea, Pinus, Abies | MN178514 | MN178543 | MZ404607 | MN203527 |
| PBM1922 (WTU) | Washington | Picea, Pinus, Tsuga, Pseudotsuga | — | EU600879 | — | EU600878 | |
| SDA470 (TENN-F-074895) | Washington | Abies, Pseudotsuga, Pinus spp. | — | ON478242 | — | — | |
| Mallocybe sp. 6 | ADP060305 (TENN-F-063537) | Washington | Pseudotsuga | MN178513 | EU600877 | — | EU600876 |
| PBM1444 (WTU) | Washington | Populus, Abies, Pseudotsuga | OQ707214 | — | — | — | |
| Mallocybe sp. 7 | NS2563 (PDD 107312) | New Zealand | Nothofagus | MN047372 | — | — | — |
| Mallocybe sp. 8 | CFSZ12101 | China | — | OP204682 | — | — | — |
| CFSZ12091 | China | — | OP20468l | — | — | — | |
| CFSZ22975 | China | — | OP204687 | — | — | — | |
| P20 “type” | China | — | ON045553 | — | — | — | |
| PBM4749 (TENN-F-077511) | West Virginia | Picea | OQ208763 | OQ225230 | OQ866120 | OQ866121 | |
| Mallocybe sp. 9 | UBC F19404 (as terrigena) | British Columbia | Pseudotsuga, Arbutus | HQ604783 | HQ604783 | — | — |
| UBC F19332 (as terrigena) | British Columbia | Pseudotsuga, Thuja | HQ604779 | HQ604779 | — | — | |
| UBC F19432 (as terrigena) | British Columbia | — | HQ604780 | HQ604780 | — | — | |
| DAVFP 28178 (as terrigena) | British Columbia | Pseudotsuga | HQ650752 | — | — | — | |
| BK0306992(UTC) | Washington | Pseudotsuga, Arbutus | — | AY038315 | — | — | |
| M. siciliana | AMB18273 | Italy | Salix | MG757416 | MG757418 | — | — |
| AMB18274 | Italy | Salix | MG757417 | MG757419 | — | — | |
| JV7987 (WTU) | Finland | Pinus, Picea, Salix, Betula, Alnus on calcareous | — | EU569834 | — | — | |
| M. squamosodisca comb. nov. | LVK20133 (TENN-F-077383) | Maine | ground | MZ404935 | MZ375436 | MZ405014 | |
| LVK22053 | Maine | Quercus, Pinus | — | — | — | — | |
| PBM4307 (TENN-F-074869) | Tennessee | Quercus, Pinus | MT196944 | — | — | MZ405015 | |
| PBM459l (TENN-F-075758) | North Carolina | Pinus, Tsuga, Quercus, Betula | OP046395 | OP046374 | — | OP060366 | |
| PBM462l (TENN-F-075791) | New York | Pinus, Abies, Betula, Populus | OP046396 | OP046375 | — | — | |
| REH7036 (NY01034397) | Costa Rica | Quercus, Comarostaphylis | OP048953 | — | — | — | |
| M. squarroso-annulata | Kuhner 63–236 (G, type) | Switzerland | — | HM209795 | — | — | — |
| M. subflavospora | E5880 (PERTH 07609256, type) | Western Australia | Eucalyptus, dry sclerophyll | — | AY380396 | AY351820 | AY351821 |
| NLB1078(PERTH 08578931) | Western Australia | Allocasuarina, Eucalyptus, woodland | MN178515 | MN178544 | — | MH577504 | |
| NLB915 (PERTH 08320861) | Western Australia | Eucalyptus | KP641619 | KP171074 | — | KM656118 | |
| PBM379l (TENN-F-067023) | Queensland | Eucalyptus, wet sclerophyll | KP641620 | KP171075 | — | KM656119 | |
| PBM3677 (PERTH 08319081) | Western Australia | Allocasuarina, dry sclerophyll | KP641621 | KP171076 | — | KM656120 | |
| M. subflavospora aff. | PBM3763 (TENN-F-066995) | Queensland | Eucalyptus, dry sclerophyll | — | MN178545 | MN203511 | MH618248 |
| M. subgranulosa | EL11–12 | Sweden | Pinus, Salix | OQ448535 | OQ448535 | — | — |
| P. Karsten 2499 (H, type) | Finland | — | OQ448532 | — | — | — | |
| M. substraminipes | CLC1375 (MONT) | Colorado | Salix | GU980605 | GU980605 | — | — |
| CLC1649 (MONT) | Colorado | Dryas | GU980602 | GU980602 | — | — | |
| CLC1731 (MONT) | Colorado | Dryas, Salix | GU980603 | GU980603 | — | — | |
| CLC2292 (MONT) | Colorado | Salix | GU 980604 | GU 980604 | — | — | |
| EL30–07 (GB) | Sweden | Dryas, Salix | GU980599 | GU980599 | — | — | |
| EL83–07 (GB) | Sweden | Salix | FN550935 | FN550935 | — | — | |
| EL99–07 (GB) | Sweden | Salix | GU 980600 | GU 980600 | — | — | |
| Kühner70–148 (G, type) | France | Dryas | GU980601 | GU980601 | — | — | |
| PBM1529 (WTU) | Wyoming | Picea, Abies | — | EU569835 | — | — | |
| T10763 (WTU) | Alaska | Salix, Alnus | — | EU569836 | — | — | |
| M. subtilior | E00116332 (E) | Sabah (Malaysia) | in flower pot | MN178516 | MN178546 | — | — |
| E9112 (PERTH 08095388) | Western Australia | — | KP641628 | KP171082 | — | — | |
| E4810(PERTH 07660634) | Western Australia | Eucalyptus | KP641628 | KP171083 | — | — | |
| MDB F75/ll (PERTH 08383081) | Western Australia | Corymbia, Acacia, Triodia, red sand woodland | KP641629 | KP171084 | — | KM656125 | |
| OKM2463l (PERTH 08561745, type) | Western Australia | Eucalyptus, sand | — | AY380398 | AY351823 | AY337406 | |
| M. subtomentosa comb. nov. | DPL13020 | Mexico | Pinus | OP046397 | — | — | — |
| DPL13025 | Mexico | Pinus | OQ208764 | — | — | — | |
| LVK14251 | Maine | Pinus strobus | MN178517 | — | — | — | |
| LVK16004 (TENN-F-077382) | New Jersey | Pinus, Quercus | MN178518 | MN178547 | — | MN203528 | |
| LVK16006 | New Jersey | Pinus, Quercus | MN178519 | MZ375437 | — | MZ405016 | |
| LVK16235 | New Jersey | Pinus, Quercus | — | MN178548 | MN203512 | MN203529 | |
| LVK17005 | New Jersey | Pinus, Quercus | MN178520 | — | — | — | |
| ME12_A6 | Alaska | Arctic | JX436908 | — | — | — | |
| M0207009 | Pennsylvania | Conifer grove, grass | — | — | — | MN203530 | |
| PBM2460 (TENN-F-062321) | Massachusetts | Mixed woods including Pinus, Quercus | MN178521 | MN178549 | MN203513 | MN203531 | |
| PBM3910 (TENN-F-068440) | North Carolina | Pinus, Quercus, Betula | OP046398 | — | — | — | |
| PBM4701 (TENN-F-75838) | New York | Mixed conifers and hardwoods | ON503076 | — | — | — | |
| PBM4763 (TENN-F-077551) | West Virginia | Tsuga, Betula, Pinus strobus, acidic soil | OQ707212 | — | — | — | |
| SAT9923301 (WTU) | New Mexico | Pinus, Quercus, Pseudotsuga | — | AY380373 | AY351799 | AY388644 | |
| M. terrigena | EL22–99 (GB) | Estonia | Picea, calcareous | AY586680 | AY586680 | — | — |
| EL24–08 (GB) | Wyoming | Salix | GU980648 | GU980648 | — | — | |
| EL117–04 (GB) | Sweden | Picea, calcareous | AM882864 | AM882864 | — | — | |
| JV16431 | Finland | Pinus, Picea, Salix, Betula, Populus, calcareous soil | — | AY380401 | AY333301 | AY333309 | |
| PBM1563 (WTU) | Wyoming | Picea, Abies | — | MN178550 | MN203514 | — | |
| M. tomentella sp. nov. | SAT0622810 (WTU) | Alberta | — | MN178508 | MN178539 | OQ872543 | — |
| PBM4690 (TENN-F-075826, type) | New York | Mixed conifers and hardwoods | OP046400 | OP046376 | OP060360 | OP060367 | |
| PBM4694 (TENN-F-075831) | New York | Mixed conifers and hardwoods | — | ON478244 | — | — | |
| M. tomentosula | GF232l (TLXM) | Mexico | Pinus cembroides | KR817255 | — | — | — |
| HRL0027 (TENN-F-071134) | Quebec | Pinus strobus | KX897446 | — | — | — | |
| PBM4138 (TENN-F-071837) | Tennessee | Quercus, Juniperus, limestone quarry | MG773814 | MK421969 | MK415443 | MH577506 | |
| RAS123 (TENN-F-071659) | Tennessee | Quercus, Juniperus, limestone quarry | MF992166 | MF797642 | — | — | |
| M. umbrinofusca | Kühner70–38(G, type) | France | Salix | GU980613 | — | — | — |
| M. unicolor | iNAT:53190985 (TENN-F-076529) | Iowa | Hardwood forest | ON503067 | OP046377 | OP06036l | OP060368 |
| MK06181501 (TENN-F-073747) | Illinois | Quercus | MH578008 | — | — | — | |
| MK06231101 (TENN-F-073748) | Illinois | Hardwoods | MH578010 | — | — | — | |
| MK08281401 (TENN-F-074753) | Illinois | Quercus, Carya | MH578009 | — | — | — | |
| PBM1481 (WTU) | Missouri | Quercus, Carya, karst | — | AY380403 | AY351827 | AY337409 | |
| PBM2645 (TENN-F-062476) | North Carolina | Quercus, Fagus | MN178522 | MN178551 | — | — | |
| PBM2940 (TENN-F-062698) | Tennessee | Carya, Fagus, karst | MN178523 | MN178552 | — | — | |
| PBM2974 (TENN-F-062732) | Tennessee | Quercus, lawn, karst | MN178524 | JQ313569 | MN203515 | MN203532 | |
| REH5532 (WTU) | New York | Quercus, Fagus | — | MN178553 | — | MN203533 | |
| RV7/4 (DUKE) | North Carolina | — | DQ490637 | AF042617 | — | — | |
| SH082407–01 (TENN-F-063553) | New Jersey | Quercus, lawn | MN178525 | MN178554 | MN203516 | MN203534 | |
| M. velutina | MSM0048 (LAH310057, type) | Pakistan | Pinus | MK990129 | MK999927 | — | — |
| MSM0049 | Pakistan | Pinus | MK990130 | MK999928 | — | — | |
| MSM00050 | Pakistan | Pinus | MK990131 | MK999929 | — | — | |
| OUTGROUPS | |||||||
| Auritella brunnescens | PBM3173 (TENN-F-065354) | New South Wales | Eucalyptus, dry sclerophyll | KJ702343 | JQ313558 | MK415420 | KJ702348 |
| Crepidotus applanatus | PBM717 (WTU) | Washington | Hardwood log, mixed Pseudotsuga forest | DQ202273 | AY380406 | AY333303 | AY333311 |
| Inosperma mutatum | PBM2542 (TENN-F-062387) | Massachusetts | Quercus | — | AY732212 | DQ447917 | DQ472729 |
| Inosperma rimosoides | PBM2459 (TENN-F-062320) | New York | Quercus, Pinus, Carya, Juniperus, calcareous | DQ404391 | AY702014 | DQ447915 | DQ385884 |
| Tubariomyces sp. | BB6018 (PC) | Zambia | Miombo woodland | MK421964 | EU600887 | MK415448 | EU60088 |
Taxon sampling
A list of taxa included in the phylogenetic analyses is presented in Table 1, including specimen-voucher number (where relevant), herbarium designation (if known), geographic origin, ecology (if known, including plant host information and edaphic factors), and GenBank accession numbers. DNA sequences of rpb1, rpb2, ITS, and 28S were used primarily from the following studies: Matheny et al. (2002, 2009), Matheny (2005), Ryberg et al. (2008), Larsson et al. (2009), Alvarado et al. (2010), Cripps et al. (2010), Ryberg et al. (2010), Vauras & Larsson (2011), Kosentka et al. (2013), Ariyawansa et al. (2015), Horak et al. (2015), Matheny & Bougher (2017), Crous et al. (2020), Aignon et al. (2021), Saba & Khalid (2020), Mao et al. (2022), and Hu et al. (2023). Blastn searches of sequences in GenBank that resulted in high similarity also led to inclusion of several ad hoc sequences (e.g., Roy et al. 2009, Meza-Meneses et al. 2016), environmental sequences, and unpublished sequences. These are also included in Table 1.
Phylogenetic analyses
DNA sequences were aligned using ClustalX v. 2.0.9 (Larkin et al. 2007) and viewed and manually adjusted as nexus files in AliView v. 1.11 (Larson 2014). Outgroup sequences included Auritella brunnescens, Crepidotus applanatus, Inosperma aff. mutatum, Inosperma rimosoides, and Tubariomyces sp. following Matheny et al. (2020). Intron regions were identified following Matheny et al. (2002) and Matheny (2005). Data were partitioned by rDNA gene regions combined, 1st, 2nd, and 3rd codon positions separately, and RNA polymerase II intronic regions combined (Matheny et al. 2002, Matheny 2005). Because of their high divergence, sequences of ITS, intron-1 and intron-4 of rpb1, and intron-4 of rpb2 were excluded from outgroups to facilitate alignments of the ingroup.
Three unlinked gene alignments were analyzed first. This included rpb1 (conserved domains A to C), rpb2 (conserved domains 6 to 7), and the ITS and 28S nuclear rDNA region combined. Maximum likelihood (ML) analyses were conducted in RAxML v. 8.2.9 (Stamatakis 2014) with 1 000 rapid bootstraps. Models of evolution used in ML analyses followed recommendations in the RAxML user manual (Stamatakis 2014), thus we applied a GTRCAT approximation to bootstrap trees, which was recommended for data sets with > 50 taxa. Any strongly intergenic conflicts (> 70 % bootstrap for incongruent groups) were noted before consideration of a final concatenated alignment.
We then assembled a 4-locus concatenated supermatrix partitioned into five-character sets (rDNA, the three codon positions separately, and RNA polymerase II introns combined) and conducted ML (see above) and Bayesian inference (BI) analyses in MrBayes v. 3.2.6 (Ronquist et al. 2012). Models used for each partition followed Matheny (2005). For all BI analyses, convergence diagnostics were examined to evaluate proper execution. These included examination of the standard deviation of split frequencies (reaching < 1.0 to ensure run convergence), potential scale reduction factors (PSRF) near 1.0, and effective samples size (ESS) > 100 for all parameters. Burn-in values of 25 % were applied, where tenable, or determined based on run convergence. We also performed a partitioned analysis of the 4-locus dataset in IQ-TREE v. 1.6.12 with 1 000 ultrafast (UF) bootstraps and the SH-aLRT test (SH) (Nguyen et al. 2015, Chernomor et al. 2016, Hoang et al. 2018). Any ML bootstrap proportions > 70 % were considered as evidence for strong support. Strong support was also noted if a clade received SHaLRT > 80 % and UF bootstraps > 95 %.
The four alignments (rpb1, rpb2, nuc rDNA, 4-locus supermatrix), ML bipartition files including branch values and gene partitioning schemes, have been archived at FigShare (doi: 10.6084/m9.figshare.23604333).
Muscarine bioassays
Eleven samples of Mallocybe were subjected to mass spectrometry analysis for detection of muscarine, an alkaloid that stimulates the parasympathetic nervous system in animals (Kosentka et al. 2013). The samples included M. heimii (JV14932F), M. isabellina (NLB800/TENN-F-066800), M. leucoblema (PBM1539/WTU), M. luteobasis sp. nov. (PBM4437/TENN-F-075309), M. montana sp. nov. (PBM3872/ TENN-F-067500/type), M. myriadophylla (JV5968f/wTU), M. praevillosa comb. nov. (FLAS-F-61523), M. sabulosa (NLB901/
TENN-F-066809), M. squamosodisca comb. nov. (PBM4621/ TENN-F-075791), M. subtomentosa comb. nov. (PBM3910/ TENN-F068440), and Mallocybe sp. 5 (PBM1922/WTU). These species were selected for this analysis because they are widely distributed across the Mallocybe phyogeny. The following samples were used as negative controls: Psilocybe caerulipes (DG21081110/TENN-F-076505, DG2108093/TENN-F-076504), Inocybe picrosma (RHM102910/TENN-F-066038), and Inosperma mucidiolens (PBM4323/TENN-F-074905) (Kosentka et al. 2013, Robbers et al. 1964, Strauss et al. 2022). Three positive controls were also used: Inocybe occulta (RAS920/TENN-F-76509), I. aff. geophylla (PBM4697/TENN-F-075834), and Inosperma aff. maculatum (PBM4522/TENN-F-075309). All three positive controls belong phylogenetically to inclusive groups known to contain muscarinic species (Kosentka et al. 2013).
The muscarine analyses were performed at the Biological Small Molecule Mass Spectrometry Core at the University of Tennessee Knoxville (RRID: SCR_021368). The analytical methodology was adapted from a previous study (Kosentka et al. 2013). Briefly, the ground samples ranging from 4–40 mg were placed into Eppendorf tubes, vortexed for 1 min, and extracted with 300 µL 4:1 Methanol:H2O at -80 °C for 20 min. All solvents used were HPLC grade. The resulting suspension was centrifuged (16 100 rcf) for five min to remove particulates. The resulting supernatants were isolated, and an aliquot was diluted by a factor of 2 000. The diluted supernatant was stored at 4 °C until LCMS analysis in UltiMate 3 000 RS autosampler (Dionex, Sunnyvale, California).
An injection volume of 10 µL was used with reversed-phase chromatography utilizing a Phenomenex Gemini 5 µm C18 column (110 Å, 150 mm × 2 mm; Torrance, California). Ultra-high-performance liquid chromatography (UHPLC) was performed utilizing an UltiMate 3 000 pump. Separations were performed with a column temperature of 25 °C and a flow rate of 150 µL/min. The separation was carried out using water (solvent A) and acetonitrile (ACN) (solvent B) for 18 min creating a gradient elution profile as previously reported (Kosentka et al. 2013). The eluent was then introduced into a Thermo Scientific Q Exactive Orbitrap MS (Thermo Scientific, San Jose, California) for ion detection.
Electrospray ionization in positive ionization mode was used as described by Kosentka et al. (2013). Muscarine was detected using parallel reaction monitoring (PRM) for the unique product m/z 56.9857 ± 5 ppm at the collision energy eV 85. A 2.0 µM solution of muscarine was used as a standard (Fisher Scientific, Waltham, Massachusetts, USA). The muscarine standard was eluted from the column at a retention time of 1.9 min. Instrumental raw data files were converted to mzML format (Chambers et al. 2012). Peak areas were integrated from extracted ion chromatograms in the open-source software package El-MAVEN (Agrawal et al. 2019). Normalized peak areas refer to area count per mg or peak area per mg since the area after blank subtraction was sample mass normalized. Samples detected with abundance less than 2.5 times of the average abundance in the blank control were considered as below the limit of detection. Although the normalized peak area does not represent absolute concentration, it corresponds to the relative abundance in the samples.
RESULTS
DNA alignments
One hundred and ninety-seven new sequences (77 ITS, 53 28S, 33 rpb1, 34 rpb2) were produced. The rpb1 dataset contained 55 taxa and 1 547 sites. The rbp2 dataset contained 98 taxa and 774 sites. The rDNA dataset (ITS1–5.8S-ITS2+28S) included 304 taxa and 2 504 sites. The combined 4-gene region supermatrix included 304 taxa and 4 823 sites. Convergence diagnostics failed for the BI analysis of the 4-gene region supermatrix and resulted in spurious placements of several taxa represented by (partial) ITS data only. For this reason, we report phylogenetic results from the RAxML and IQ-TREE analyses only.
Murrill’s Inocybe (Lepista) praevillosa is sister to Mallocybe
Both rpb1 and rpb2 gene trees (Supplementary Figs S1, S2, respectively) recovered Mallocybe as a strongly supported monophyletic group. Both trees indicated strong support for a grade of Inocybe praevillosa, originally described as Lepista praevillosa by W.A. Murrill, and the newly named Mallocybe montana giving rise to the remainder of Mallocybe described or documented from Asia, Australasia, Eurasia, and North America. Considerably denser taxon sampling of Inocybaceae and outgroups of Crepidotaceae and Tubariaceae reinforce these strongly supported results for both genes (unpubl. data). Both gene trees also recovered three main clades within the genus as previously shown by Hu et al. (2023). These three clades have yet to be named, but here we propose them informally as clades Unicolores, Nothosperma, and Mallocybe, and suggest they may be equivalent to potential subgenera depending on forthcoming revisions of European Mallocybe.
Both rpb1 and rpb2 recovered similar overarching topologies with respect to placement of Inocybe (Lepista) praevillosa and M. montana in position to the rest of Mallocybe. However, rpb1 anchored clades Nothosperma and Unicolores as a monophyletic group with strong support, whereas rpb2 recovered clades Nothosperma and Mallocybe as sister groups but with weak support. The rDNA-only tree did not recover Mallocybe as monophyletic due to the clustering of I. (Lepista) praevillosa among the outgroups, but this result was weakly supported. Clade Nothosperma was recovered as monophyletic with moderate support including a Nothofagus-associated sample from New Zealand sister to all other Australasian taxa. However, clade Mallocybe was found to be paraphyletic within which clade Unicolores and M. montana were placed.
A notable source of gene conflict was observed between the rDNA and rpb2 gene trees. This concerned the placement of the recently described species M. africana (Aignon et al. 2021). Initial analyses of our rDNA and rpb2 alignments (data not shown) placed it sister to M. errata with strong support (rDNA), or sister to the rest of Mallocybe with weak support (rpb2). Two rpb2 sequences of M. africana from the same sample (MR00385) are available in GenBank, but these differ by 4.5 % percent identity. Because of concerns regarding gene duplication and paralogs, we excluded M. africana from further downstream analyses. A close relationship between M. africana (indicated as “I. microdulcamara nom. prov”) and M. errata and M. heimii was previously recovered by Matheny et al. (2009). Until new and additional rpb1 and rpb2 sequences can be produced, we regard M. africana as incertae sedis within the genus.
The 4-locus supermatrix provides a robust phylogeny of Mallocybe
Figure 1 provides a single-page phylogenetic overview of major clades and some species-level lineages within Mallocybe and the species that reside within each. Outgroups were pruned from this figure. Figure 2 was split into three parts detailing the entire phylogram. Phylogenetic analyses of the 4-gene supermatrix recovered an overall topology most similar to the rpb2 gene tree with strong support for the union of clades Nothosperma and Mallocybe as a monophyletic group, and sister to it clade Unicolores. Similar to the rpb1 and rpb2 gene trees, both Inocybe (Lepista) praevillosa and M. montana formed a paraphyletic assemblage from which clades Unicolores and Nothosperma + Mallocybe emerged. Every one of these major nodes received strong support (> 77 % ML bootstrap) despite differences in taxon sampling depth per gene region. Overall, at least 55 species-level lineages were detected.
Fig. 1.
Summary ML phylogram of Mallocybe based on a supermatrix of combined rpb1, rpb2, ITS, and 28S sequence data. Inclusive terminal groupings are cartooned to compress the figure for easier graphic presentation. Three major clades and two unresolved species-level lineages within Mallocybe are indicated: clades Mallocybe, Nothosperma, and Unicolores and the Montana and Praevillosa lineages. Within clade Mallocybe, several strongly supported nested groups were recovered: the Arthrocystis, Fuscomarginata, Heimii, core Mallocybe, and Delecta clades, in addition to a strongly supported paraphyletic group referred to as the Terrigena grade. Numbers above or below branches represent bootstrap proportions > 70 % except for the Arthrocystis clade. Black-filled squares indicate support values for internodes with SH-aLRT > 80 % and UF bootstraps > 95 %. The scale bar indicates the number of expected substitutions per site. Outgroups have been pruned.
Fig. 2.
The ML phylogeny of Mallocybe based on a supermatrix of combined rpb1, rpb2, ITS, and 28S sequence data. Numbers above or below branches indicate bootstrap proportions > 50 %. Black-filled circles indicate support values for internodes with SH-aLRT > 80 % and UF bootstraps > 95 %. The figure is divided into three parts (A, B, C). The scale bar equals the number of expected number of substitutions per site.
Murrill’s Inocybe (Lepista) praevillosa, recombined below as Mallocybe praevillosa, was recovered as sister to all other species of Mallocybe. Murrill’s taxon is distinguished by the relatively robust but brittle basidiomes, rooting stipe, the rather pale [originally described as pale pinkish by Murrill (1942)] allantoid to cylindric basidiospores, the presence of a low relative concentration of muscarine (Fig. 3), absence of necropigmented basidia, and elongated cheilocystidia. Cystidioid elements were found on the stipe, but these were not arranged in any way similar to those that characterize species of the genus Tubariomyces (Alvarado et al. 2010). Furthermore, the pileipellis was found to be a cutis giving rise to upright and interwoven hyphae, also unlike Tubariomyces, which forms a trichodermial palisade. The species was collected by us under Quercus laurifolia near the type locality on karst topography but also on sandhills with Quercus and Pinus.
Fig. 3.
Histogram showing the relative abundance of muscarine in select species of Mallocybe presented as a log normalized peak area, which refers to area count per mg or peak per mg since the aera after blank subtraction was sample mass normalized. Samples detected with abundance less than 2.5 times of the average abundance in the blank control were considered as below limit of detection. Psilocybe caerulipes, Inocybe picrosma, and Inosperma mucidiolens were used as negative controls, and I. occulta, I. aff. geophylla, and a species in the Inosperma maculatum group were used as positive controls. Mallocybe unicolor was also shown to lack muscarine by Kosentka et al. (2013). Of eastern North American species sampled, only M. praevillosa proved to contain a relative amount of muscarine but considerably lower than detected among the positive controls and the Australian species M. sabulosa. Stijve et al. (1985) also indicated the absence of muscarine from M. terrigena, the type of Mallocybe.
Mallocybe montana (described below) was observed as sister to the remainder of Mallocybe with strong support. This species is characterized by elongated cheilocystidia, elongated cylindric basidiospores, necropigmented basidia, lack of a detectable amount of muscarine (Fig. 3), and occurrences on sandy acidic soils in mountainous regions of the Southern Appalachians.
Clade Unicolores (= Clade C in Hu et al. 2023) appeared sister to the other two major clades within Mallocybe. Here we documented that two additional species described by Murrill from Florida, M. fulviceps and M. multispora, belong to this clade. The American species in clade Unicolores are characterized often by elongated cheilocystidia, elongated cylindric spores, stipe length longer than the pileus width, and putative ectomycorrhizal relationships with Quercus and/or Pinus on limestone soils. Mallocybe unicolor, the third eastern North American species in clade Unicolores, seems to have a wide ecological amplitude, occurring abundantly in areas characterized by Quercus and Tilia on karst topography; however, the species has also been recorded, but with low basidiome abundance, on acidic soils in montane regions of the Southern Appalachians. Three East Asian species were also recovered in clade Unicolores, all of which are also characterized by elongated cheilocystidia (Hu et al. 2023). Their plant associations include Fagaceae (e.g., Castanopsis) and Salicaceae (Populus).
The second major grouping, clade Nothosperma (= Clade B in Hu et al. 2023) contained five named species from Australia and/or Malaysia and one unidentified species from New Zealand. Two species – M. subflavospora and M. pyrrhopoda – were non-monophyletic. Within clade Nothosperma, the New Zealand sample (Mallocybe sp. 7) is sister to the Australian lineages with strong support. The unpublished Mallocybe sp. 7 is characterized by elongated cheilocystidia and an association with Nothofagus, unlike the Australian species in this clade, all of which have short cheilocystidia and associations with Myrtaceae, Casuarinaceae, and Fabaceae (Matheny & Bougher 2017). Mallocybe callichroa (recombined into Mallocybe below), another Nothofagus associate from New Zealand with clavate and elongated cheilocystidia, may belong to this clade as well, but molecular confirmation is lacking. Mallocybe sabulosa was found to contain relatively high amounts of muscarine (Fig. 3), whereas M. isabellina lacked any detectable amount of the toxin.
The third major group is referred to as clade Mallocybe (= Clade A in Hu et al. 2023) and includes the generic type M. terrigena and 40 other species-level lineages primarily from temperate regions of the northern hemisphere (and three from or extending into tropical latitudes). Several mostly strongly supported inclusive groupings were also observed in clade Mallocybe. The first of these was the Arthrocystis clade containing four species, only two of which are presently described – the European species M. arthrocystis and the East Asian M. piceae, and two undescribed species from the Pacific Northwest in western North America; all analyses recovered the Arthrocystis clade as monophyletic but only with moderate support (e.g., 61 % ML bootstrap).The Fuscomarginata clade likewise included four species, two of which are known in Europe – M. fuscomarginata and M. gymnocarpa; two additional unclarified species were identified from the Pacific Northwest.
The core Mallocybe clade was recovered with strong support and was characterized by the inclusion of the Heimii clade, the Terrigena grade, and the highly diverse Delecta clade. The Heimii clade was strongly supported as sister to rest of the core Mallocybe clade with five species from the northern hemisphere including South Asia, whereas the Terrigena grade was recovered as a paraphyletic assemblage of M. luteobasis (described as new below), M. terrigena, M. fibrillosa (= I. dulcamara sensu auct. p.p., non Persoon), and M. leucoblema. The Delecta clade contains 24 species from north temperate regions, including high elevations in Central America. Within clade Mallocybe, six samples were assayed for the presence of muscarine, but the toxin was undetected in all of them (Fig. 3; see also further results below).
In total, 16 species of Mallocybe were recovered from eastern North America (four described as new below, but also one additional species that cannot be described here due to insufficient data). Of these 16 species, 11 were recovered in clade Mallocybe, three in clade Unicolores, and two corresponded to the Montana and Praevillosa lineages. Several additional and probably undescribed species were also recovered from western North America. These will be addressed and treated in a forthcoming study.
Overall, many species of Mallocybe have been characterized by broad intercontinental biogeographic distributions (Cripps et al. 2010). However, some local endemism by continent or regions of continents was suggested by our results. Species known currently only from eastern North America included several species described as new or recombined into Mallocybe below – M. leucothrix, M. montana, M. praevillosa, M. squamosodisca (including Costa Rica), M. luteobasis, and M. tomentosula (including Mexico), M. unicolor, and M. fulviceps. Two eastern North American species were also recorded from western regions and represent continental endemics to date: M. tomentella and M. multispora. All five described species from Australia appeared endemic to that continent, and the one species sampled from New Zealand is known thus far only from New Zealand.
Most species of Mallocybe lack detectable amounts of muscarine
Mass spectrometry revealed no detectable muscarine in samples of the following species: Mallocybe heimii, M. isabellina, M. leucoblema, M. luteobasis, M. montana, M. myriadophylla, Mallocybe sp. 5, M. squamosodisca, and M. subtomentosa (Fig. 3). A relatively high concentration of muscarine was detected in M. sabulosa and a relatively lower amount in M. praevillosa. As expected, none was detected in the negative controls Psilocybe caerulipes, Inocybe picrosma, and Inosperma mucidiolens. The three positive controls possessed relatively high concentrations of the toxin (Fig. 3).
TAXONOMY
Mallocybe (Kuyper) Matheny et al., Mycologia 112: 94. 2020 [2019].
Synonym: Inocybe subg. Mallocybe Kuyper, Persoonia 3 (Suppl.): 22. 1986.
Typification: Agaricus terrigenus Fr., Öfvers. K. Svensk. Vetensk.-Akad. FÖrhandl. 8(2): 46. 1851.
Description: Cheilocystidia often present and arising as terminal elements of the hyphae of hymenophoral trama, typically < 50 µm, rarely as short incrusted chains (if cheilocystidia > 50 µm long, this is generally a shared ancestral trait); pleurocystidia absent, basidia often necropigmented; lamellae usually broadly attached (adnate, uncinate, or subdecurrent), pileus typically woolly-squamulose or tomentose-fibrillose, surface often darkening with application of alkali solutions, context not reddening. Ectomycorrhizal with a wide range of plant families.
Notes: About 65 species are known in the genus and occur in Africa, Asia, Australia, Europe, New Zealand, and North America.
Mallocybe clade Mallocybe
Description: Includes Mallocybe species from the northern hemisphere, most of which are characterized by short clavate, pyriform, or cylindric cheilocystidia (often < 50 µm long). Common in north temperate zones, but also present in tropical areas of South Asia and high elevations in Central America. Muscarine not detected from most species assayed, including the type, but reported from other species: M. agardhii, I. caesariata, I. dulcamara, and M. malenconii. Putative plant family associates include Betulaceae, Cistaceae, Dipterocarpaceae, Fagaceae, Pinaceae, Rosaceae, and Salicaceae.
Currently included species (51 accepted): M. abruptibulbosa, M. agardhii, M. arthrocystis, M. attenuatipes, M. cotoneovelata, M. delecta (= M. crassivelata), M. depressa, M. errata, M. fibrillosa (= I. dulcamara sensu auct. p.p., non Persoon), M. errata, M. fulvipes, M. fulvoumbonata, M. fuscomarginata, M. granulosa, M. gymnocarpa, M. hebelomoides, M. heimii (=M. arenaria), M. homomorpha, M. lagenicystidiata, M. latifolia (= M. acystidiata), M. latispora (=M. plebeia), M. leucoblema, M. leucoloma, M. leucothrix sp. nov., M. luteobasis sp. nov., M. malenconii, M. megalospora, M. myriadophylla, M. nuptialis, M. pallidotomentosa, M. paludosa, M. parcesquamulosa, M. pelargoniodora, M. perbrevis, M. piceae, M. pseudodulcamara, M. pygmaea, M. siciliana, M. solidipes, M. squamosoannulata, M. squamosodisca comb. nov., M. squarrosoannulata, M. subannulata, M. substraminipes, M. subtomentosa comb. nov., M. terrigena, M. tomentella sp. nov., M. tomentosula, M. umbrinofusca, M. velicoronata, and M. velutina. Inocybe favrei Nespiak and I. nespiaki M. Bon are invalid names, but both species belong here. Note that Inocybe stenospora (contra Stangl 1989, Ludwig 2017), despite lacking pleurocystidia, belongs to the Inocybe lanuginosa group (Bandini et al. 2018) and not in Mallocybe as previously considered.
Notes: Most species of Mallocybe occur in clade Mallocybe upon consideration of their geographic distribution (non-Australasian), often short cheilocystidia (when present), and in most species average Q values for basidiospores < 2.0. In some species the stipe length is equal to or less than the pileus diameter. The clade includes all known arctic and alpine species. Daskalopoulos et al. (2021) noted some unique features to the ectomycorrhizal anatomy of M. heimii compared to other Inocybaceae: an open or variant anastomosis-type and presence of clamp connections on mantle hyphae.
Mallocybe clade Nothosperma
Etymology: Nothosperma (Gk.), southern seed, in reference to occurrence in the southern hemisphere.
Description: Includes Mallocybe species from the southern hemisphere (temperate and tropical regions) and tropical regions of southeast Asia (Malaysia) that associate with Myrtaceae, Casuarinaceae, and Nothofagaceae. Most species characterized by presence of short cheilocystidia (< 50 µm long); stipe often longer than the pileus diameter; pileipellis hyphae coarsely incrusted. Muscarine detected at relatively high concentration in M. sabulosa. No species have yet been recorded from South America.
Currently included species (seven accepted): M. isabellina, M. pyrrhopoda, M. sabulosa, M. subflavospora, and M. subtilior from Australia, M. althofiae from New Guinea, one unclarified species from Malaysia in association with Allocasuarina, and one unclarified species from New Zealand found with Nothofagus. Inocybe callichroa (Horak 2018) described from New Zealand, is placed here as well (see Taxonomy below). The occurrence of M. cf. subtilior in Sabah, Malaysia, was confirmed after sequencing a specimen from a flowerpot on bare earth (leg. E.J.H. Corner, 13 May 1964, E00116332). This species is likely introduced. However, another collection (E00116333) made by Corner from Johor, Malaysia, was made from bare sand in front of “Casuarina״. This is an undescribed Mallocybe species characterized microscopically by large “laceroid״ basidiospores (similar to Inocybe lacera in outline), 11.5–12.4–14(–14.5) × (5.5–)6–6.2–6.5(–7) µm, Q 1.85–2.02–2.33, short articulated cheilocystidia (28–45 × 12–25 µm), and presence of necrobasidia (Matheny 2003). No field notes accompanied the duplicate collection at Herbarium E. However, the combination of habit (stipe longer than the pileus diameter), small size, and coarsely incrusted pileipellis hyphae point to a relationship with Australian species of Mallocybe.
Mallocybe clade Unicolores
Etymology: Unicolores (L.), named after the oldest binomial in the clade, Mallocybe unicolor.
Description: A monophyletic group of Mallocybe species from East Asia and North America with distinct or elongated (> 50 µm long) cheilocystidia, stipe length generally longer than the pileus width, and association with angiosperms (Fagales, Malvales) and Pinus. Basidiospores with mean Q values > 1.90.
Currently included species (six accepted): M. aurantiidisca, M. fulviceps, M. longicystis, M. pallidipes, M. multispora, and M. unicolor. Known from eastern North America and East Asia.
Montana lineage
Description: A single stem lineage sister to clades Unicolores, Nothosperma, and Mallocybe. Characterized by elongated cheilocystidia, oblong-cylindric basidiospores, and narrow-range endemism in the Southern Appalachian Mountains in association with Betulaceae, Fagaceae, and/or Pinaceae. KOH dark on the pileus surface; necrobasidia present.
Currently included species (one accepted): M. montana (described as new below). Known only from the southeastern U.S.
Praevillosa lineage
Description: A single stem lineage sister to clades Unicolores, Nothosperma, and Mallocybe and the Montana lineage. Characterized by elongated cheilocystidia, oblong-cylindric to allantoid pale basidiospores, and narrow-range endemism in northern Florida in association with Fagaceae. KOH negative on pileus surface; necrobasidia not observed.
Currently included species (one accepted): M. praevillosa (recombined as new below). Known only from the southeastern U.S.
Mallocybe incertae sedis
Mallocybe africana Aïgnon, Yorou & Ryberg, Phytotaxa 478: 53. 2021.
Species taxonomy
Mallocybe fibrillosa (Peck) Matheny & Esteve-Rav., Mycologia 112: 106. 2019 [2020]. Figs 4A–C, 9A–C.
Fig. 4.
Basidiomes of Mallocybe from eastern North America. A. M. fibrillosa (LVK14371, photo L. Kudzma). B. M. fibrillosa (REH10168, photo R. Halling). C. M. fibrillosa (PBM2350, photo B. Matheny). D. M. fulviceps (DPL13914, photo D. Lewis). E. M. fulviceps (PBM4533, photo B. Matheny). F. M. fulviceps (PBM4726, photo B. Matheny). G. M. latifolia (LVK22088, photo L. Kudzma). H. M. latifolia (PBM3731, photo B. Matheny). I. M. latifolia (MES3796, photo M. Smith). J. M. leucothrix (PBM4541, holotype, photo B. Matheny). K. M. leucothrix (PBM4531, photo B. Matheny). Scale bars = 1 cm.
Fig. 9.
Microscopic features of Mallocybe. A. Basidiospores of M. fibrillosa (isotype). B. Cheilocystidia of M. fibrillosa (isotype). C. Basidiospores of M. fibrillosa (isotype of Inocybe subdecurrens). D. Basidiospores of M. fulviceps (isotype). E. Cheilocystidia of M. fulviceps (isotype). F. Cheilocystidia of M. fulviceps (isotype of I. pertomentosa). G. Basidiospores of M. fulviceps (isotype of I. pertomentosa). H. Basidiospores of M. fulviceps (isotype of I. vialis). I. Cheilocystidia of M. fulviceps (isotype of I. vialis). J. Basidiospores of M. fulviumbonata (holotype). K. Cheilocystidia of M. fulvioumbonata (holotype). L. Basidiospores of M. latifolia (PBM4537). M. Cheilocystidia of M. latifolia (PBM4537). Scale bars = 10 µm for spores; 25 µm for cystidia.
Basionym: Inocybe fibrillosa Peck, 1888, non (Cleland) Grgur., Larger Fungi of South Australia: 190. 1997.
Synonyms: Inocybe dulcamara Sacc., Syll Fung 5:764. 1887 (nom. illegit., Art. 53.1), non Inocybe dulcamara (Pers.) P. Kumm., Führ. Pilzk.: 79. 1871.
Agaricus dulcamarus Alb. & Schwein., Schr. Naturf Ges, Leipzig: no. 489. 1822 (nom. illegit. Art. 53.1), non Agaricus dulcamarus Pers., Syn. Meth. Fung. 2: 324. 1801.
Inocybe subdecurrens Ellis & Everh., J. Mycol. 5: 26. 1889. Mallocybe subdecurrens (Ellis & Everh.) Matheny & Esteve-Rav., Mycologia 112: 108. 2019 [2020].
Inocybe caesariata sensu Kauffman, N. Am. Fl. 10(4): 255. 1924.
Pileus 15–40 mm wide, convex to plano-convex and eventually plane, margin incurved or inrolled at first and remaining so after expansion or becoming decurved, rarely subumbonate; surface dry, velipellis absent, heavily matted fibrillose to matted radially lanose or tomentose-fibrillose, disc at time with fibrillose scales, with white veil remnants when young; light brown (6C6–D6 or 6D5), brownish yellow, or fulvous throughout (10YR 5/6; Buckthorn Brown) brown with 3 % KOH, with cobwebby veil remnants at margin; context off-white, very pale brown, to yellowish white, unchanging where bruised, solid becoming hollow, odor mild or subtly sweet, taste mild. PDAB negative, guaiac dark olive green. Lamellae uncinate or subdecurrent to adnate, adnexed, close (up to 40 L) and with several tiers of lamellulae, light olive brown to olive brown (2.5Y 5/4–4/4), edges even or pallid and indistinctly fimbriate. Stipe 10–35 × 5–10 mm, equal, strict or curved; surface dry, heavily lanose to matted sublanose to squamulose, nowhere pruinose and not at all scaly, rarely peronate, with obvious partial veil remnants as a cortinate veil; light brown (lighter in color than the pileus surface) or with pale yellow ground color (2.5Y 2/4), white at the base; context solid becoming hollow, pale dingy yellow to olive yellow but nowhere bright yellow.
Basidia (26–)29–41 × 6–9 µm, 4-sterigmate, slenderly clavate, hyaline to ochraceous, necropigmented. Basidiospores (7.5–)8– 9.0–9.5(–10) × 4.5–5.0–5.5(–6) µm, Q (1.50–)1.55–T.7б–1.90(– 2.24), smooth, elliptic, subphaseoliform, to (sub)amygdaliform with obtuse to bluntly pointed apices, with thickened walls, apiculus small and indistinct, ocher-buff to ochraceous-tawny (n = 53/3). Pleurocystidia absent. Cheilocystidia 16–45 × 9–14 µm, cylindric to clavate, occasionally flexuous, utriform, or short fusiform, apices obtuse or swollen, thin-walled, hyaline, edges of lamellae sterile. Caulocystidia not observed in the type but present as short clavate cells (at times elliptic or cylindric) at the extreme apex in PBM2350, usually hyaline, thin-walled; vesture hyphae brownish yellow in mass, incrusted, cylindric and up to 16 µm wide; stipe hyphae subhyaline in mass, refractive hyphae present. Pileipellis a cutis of parallel to subparallel hyphae, at times scattered upwards or tangled, tawny to brownish yellow in mass, hyphae cylindric, incrusted, 7–15 µm wide; tramal hyphae pale yellowish in mass, at times inflated, refractive hyphae present. Lamellar trama parallel, compact, pale yellowish or light yellowish brown in mass, hyphae cylindric and 7–15 µm wide. Clamp connections present.
Distribution: Widely distributed in the northeastern USA (Maine, New Jersey, New York), southeastern Canada (Quebec), the Pacific Northwest (British Columbia, Washington) and in the Rocky Mountains (Colorado, Wyoming), also northern Europe.
Habitat: On soil (at least some sites acidic) in mixed forests but with Pinus or other Pinaceae often present, also with Salix, and possibly Dryas in alpine areas of the USA, and with Populus in western subalpine areas, occurring with Salix or Betula in Europe. August–October in eastern North America, July–August in western North America.
Specimens examined: USA, Maine, Somerset Co., West Forks, Main Huts Trail (east end along Dead River), on ground in mixed woods, 19 Sep. 2014, L.V. Kudzma, LVK14371 (pers. herb.); Maine, Somerset Co., the Forks, Moxie Falls Trail, 20 Sep. 2014, L.V. Kudzma, LVK14390 (pers. herb.); ibid., 22 Sep. 2015, L.V. Kudzma, LVK15242 (pers. herb.); Main, Limestone, Aroostook Co., Aroostook National Wildlife Refuge, on soil in mixed woods under Picea, Abies, Betula, Larix, Populus, 10 Sep. 2022, L.V. Kudzma, LVK22085 (pers. herb.); New Jersey, Gloucester Co., Newfield, under overhanging limbs of Norway spruce (Picea), Oct. 1887, Ellis & Everhart (holotype of Inocybe subdecurrens, NY 00775657, 00775658, 007775659, 00775660); Somerset Co., Woods Road School, under pine, 7 Oct. 1995, R.M. Fatto, RMF908 (NY 673247); ibid., under conifers, 12 Oct. 1996, R.M. Fatto, RMF1009 (NY 673246); New York, Albany Co., Bethlehem, Corning Farm, on damp mossy banks in woods, Aug. (no day and year), C.H. Peck s.n. (isotype WTU part of NYSf1175); Essex Co., Peck Foray at the State University of New York (SUNY) College of Environmental Forestry (EFS) Newcomb Campus, Huntington Forest Preserve, 43.96929 -74.22022, 507 m elev., gregarious on soil under Abies, Picea, Betula, Thuja, Pinus, no date, R.E. Halling, REH10168 (NY 2861422, TENN-F-073177); Washington, King Co., exit 47 off Interstate 90, Pratt Lake Trail, scattered along moist bank along trail in second growth conifer forest dominated by Pseudotsuga and Tsuga, 25 Aug. 2002, P.B. Matheny, PBM2350 (WTU).
Other specimens examined (Mallocybe delecta): Finland, Tavastia australis, Tammela, Syrjä, no date, P.A. Karsten, 1636 (holotype of Agaricus delectus, H); ibid., P.A. Karsten, 1637 (isotype of Agaricus delectus, H).
Notes: The name Mallocybe fibrillosa (syn. I. fibrillosa Peck) has not been widely used since synonymized with I. caesariata by Kauffman (1924) but in our judgement conforms to application of the name Inocybe dulcamara used by Cripps et al. (2010; see further discussion below about conflicting concepts for this species). We suggest that modern extant material studied from New York (NY 2861422) and elsewhere in northeastern states serves as adequate reference material for Peck’s Inocybe fibrillosa originally described from the greater Albany area in New York. The species is characterized generally by the tomentose-fibrillose pileus, olivaceous hues to the moderately spaced lamellae, the tomentose to lacerate-fibrillose stipe with a white base, and, according to Cripps et al. (2010, as I. dulcamara), an odor of honey or burnt sugar. Washington material of M. fibrillosa exhibited a sweet earthy smell. The spores are not oblong and have a mean Q value less than 2.0. The cheilocystidia are short and generally cylindric. Cripps et al. (2010) reported the presence of 2-sterigmate basidia in some alpine collections and thus larger spores. Ecologically, the species is widespread, occurring in northern Europe and eastern and western North America at high latitudes or high elevation, including alpine areas (as confirmed by molecular data). The species may have a circumboreal distribution. The plant host range overall is somewhat broad and includes Pinaceae, particularly Pinus but also other genera, Salicaceae (Salix, Populus), Betulaceae (Betula), and Rosaceae (Dryas). Among other species that occur in eastern North America, M. subtomentosa differs from M. fibrillosa by the stipe length that is longer than the pileus width and the nearly smooth pileus. Malllocybe squamosodisca can be distinguished from M. fibrillosa by the cracked-areolate pileus surface that develops with age, longer spores on average, and the lack of any odor as well.
Our concept of M. fibrillosa is the same as that documented from western North America and Europe as I. dulcamara by Cripps (1997, in the sense of Albertini and Schweinitz) without molecular data and by Cripps et al. (2010, as I. dulcamara (Alb. & Schwein.) P. Kumm.) with molecular data. However, Agaricus dulcamarus Alb. & Schwein. 1822 is a later homonym of Agaricus dulcamarus Pers. 1801 and thus an illegitimate name per ICN Art. 53.1. Neither name was included in any sanctioning works of Fries. Inocybe dulcamara Sacc. 1887 is a homotypic synonym of Agaricus dulcamarus Alb. & Schwein. and is illegitimate because it is a later homonym of Inocybe dulcamara (Pers.) P. Kumm. 1871.
Agaricus dulcamarus Pers. represents a different species than interpreted by many modern authors including Ricken (1915), Heim (1931), Kühner & Romagnesi (1953), Favre (1955), Malloch (1973), Cripps et al. (2010), and that documented by Favre (1955), per Cripps and colleagues, as I. dulcamara ‘forma typique’. The description in Persoon’s protologue (Persoon 1801), and later an icon (Persoon 1803–1806) of Agaricus dulcamarus Pers. conflicts with the later interpretation of I. dulcamarasensu auct. p.p. (Matheny 2003). Persoon’s fungus may actually represent Inosperma cervicolor (T.W. Kuyper, pers. comm.). Fries (1828) interpreted A. dulcamarus as his A. lucifugus, a name treated by Kuyper (1986) as a nomen dubium. Singer (1986) preferred to use the name Inocybe delecta in lieu of I. dulcamara (Alb. & Schwein.) P. Kumm. We examined the type collections of Agaricus delectus [H, No. 1636 (holotype) and 1637 (isotype)] and found the spores to be somewhat narrower and more oblong (8–9.010 × 4–4.6–5 µm, Q 1.80–l.95–2.13(–2.38)) than in M. fibrillosa. Since our examination of the types, Ellen Larsson (University of Gothenburg) was able to produce a molecular annotation (ITS) from the type of Mallocybe delecta (H, No. 1636; OQ448533) and modern reference material (JV21393; OQ448534 – ITS and 28S). Sequences from both samples cluster with strong support in a species-level lineage with M. crassivelata. Thus, we can safely eliminate the possibility of any conspecificity between M. fibrillosa and M. delecta.
The application of the name I. dulcamara (Fr.) Quél. by Stuntz (1947; Stz. 805), collected under high-elevation conifers in Washington, likely represents a different species, possibly M. gymnocarpa or a closely related species, based on the large size of the basidiomes, spore morphology, and absence of a veil.
Stuntz (1947) considered I. subdecurrens and I. tomentosa Ellis & Everh. (non Quél.) as synonymous, as others did before him (Kauffman 1924, Smith 1939), and applied the name I. subdecurrens to a single lowland collection under Alnus from lowland Washington state. From this single collection Stuntz noted a white ample cortina, the stipe longer than the pileus width, relatively narrow spores (8–10 × 4.5–5.5 µm), and pyriform to short-clavate articulated cheilocystidia. Stuntz’ collection may fit M. leucoloma (see discussion under M. subtomentosa). Peck published Inocybe fibrillosa in 1888, which precedes by one year the publication of I. subdecurrens, hence, when considering the two as synonymous, I. fibrillosa has priority.
In the study by Matheny et al. (2020), M. fibrillosa was referred to as I. subdecurrens. The holotype of I. subdecurrens comprises three packets and four elements, all from the same original gathering and fixed to a single sheet at NY. Attempts to sequence two elements of the holotype (775657 and 775658) failed due to poor quality reads and sequence heterogeneity. We did not attempt to sequence the type of I. fibrillosa. Because we cannot distinguish the two species morphologically and ecologically, we regard them as the same with M. fibrillosa holding nomenclatural priority by a single year.
Phylogenetic analyses (Fig. 2A) support multiple samples from North America and Europe, including alpine and non-alpine populations, as a strongly supported clade. The geographic and ecological extent of M. fibrillosa in Europe awaits further revision.
Mallocybefulv¡ceps (Murrill) Matheny & Esteve-Rav., Mycologia 112: 106. 2019 [2020]. Figs 4D–F, 9D–I.
Basionym: Inocybe fulviceps Murrill, Quart. J. Florida Acad. Sci. 8: 187. 1945.
Synonyms: Inocybe pertomentosa Murrill, Quart. J. Florida Acad. Sci. 8: 189. 1945.
Inocybe vialis Murrill, Quart. J. Florida Acad. Sci. 8: 191. 1945.
Pileus 10–28 mm wide, obtusely conical to convex or subexpanded with a small pointed or low broad umbo; margin incurved, becoming decurved with age; surface dry, appressed tomentose-fibrillose to fibrillose-scaly, velipellis absent; fulvous or yellowish brown (10YR 5/6; near Buckthorn Brown or a shade lighter), at times paler over the disc, dark brown with 5 % KOH; context very thin, pallid with a pale yellow tone, odor spermatic, at least when first cut, or somewhat acidulous. Lamellae sinuate to uncinate, subdistant to moderately close with ca. 20–24 L and several tiers of lamellulae, ventricose, broad; pallid to yellowish brown becoming dark yellowish brown with age; edges pallid, indistinctly fimbriate. Stipe 10–33 × 2–3 mm, equal, not bulbous; surface dry, cortina fugacious and composed of fulvous fibrils, tattered fibrillose entire length, not scaly but on occasion with scattered bands of fibrils; pale yellow (2.5Y 7/4); context solid, pale yellow throughout including in the base.
Basidia 27–35 × 9–10 µm, 4-sterigmate, clavate, hyaline or necropigmented. Basidiospores (9.5–)10–11.0–13(–14) × (4.5–)5–5.1–5.5(–6) µm, Q 1.90–2.15–2.56 (n = 85/5), smooth, oblong-elliptic, oblong-phaseoliform, less often subamygdaliform, with obtuse apices; thick-walled, ochraceous-buff, apiculus small and indistinct. Pleurocystidia absent. Cheilocystidia 28–48 × 11–16(–22) µm, clavate to utriform but saccate and obovate cells also observed; thin-walled, hyaline; edges sterile. Caulocystidia in clusters, similar to cheilocystidia; stipe hyphae yellowish in mass, cylindric, 4–9 µm wide, weakly incrusted, refractive hyphae not observed. Pileipellis a cutis of parallel hyphae, yellowish brown to ochraceous in mass, hyphae cylindric, up to 15 µm wide, incrusted. Lamellar trama parallel, pale yellowish brown to subhyaline in mass, hyphae cylindric, up to 15 µm wide. Clamp connections present.
Distribution: Southeastern USA (Florida, Louisiana).
Habitat: Scattered to gregarious, singly or in small clusters on sandy soil on karst topography in mixed forests of Quercus and Pinus or under hardwoods such as Carpinus and Quercus, including Q. nigra, also in disturbed areas such as roadsides. July-December.
Specimens examined: USA, Florida, Alachua Co., Gainesville, 11 Aug. 1944, W.A. Murrill, F18506 (isotype of Inocybe fulviceps WTU, isotype TENN-F-021186); Alachua Co., Gainesville, gregarious in a path shaded by frondose trees, 20 Sep. 1944, W.A. Murrill, F20017 (isotype of Inocybe vialis WTU, holotype FLAS-F-20017); Alachua Co., Gainesville, gregarious to caespitose in moist shaded soil, no date, W.A. Murrill, F19657 (isotype of Inocybe pertomentosa WTU, isotype TENN-F-021192); Alachua Co., Gainesville, University of Florida, Natural Area Teaching Lab, 29.63389 -92.368728, 25 Aug. 2017, Florida Mycological Foray (FLAS-F-61501); Alachua Co., Wood Creek neighborhood, Gainesville, under Quercus virginiana, Q. nigra, 19 Sep. 2020, M.E. Smith, MES-3773 (FLAS-F-66615); Alachua Co., Alachua, Mill Creek Preserve, West Trail, on sandy soil under Pinus palustris, other Pinus, and Quercus, 6 Jul. 2022, R.A. Swenie, PBM4715 (TENN-F-077389); ibid. P.B. Matheny, PBM4718 (TENN-F-077392); ibid., P.B. Matheny, PBM4722 (TENN-F-077396); Alachua Co., Gainesville, on sandy soil under Carpinus, Quercus, Blues Creek Ravine Preserve, 7 Jul. 2022, P.B. Matheny, PBM4726 (TENN-F-077450); Polk Co., Circle B Bar Reserve, Lakeland, on soil near a trail, 22 Oct. 2016, S.-Y Wu, MES2993 (FLAS-F-66574); Putnam Co., Ordway-Swisher Biological Station (UF), near west entrance, 45 m elev., gregarious to scattered singly or in small clusters on sandy soil on side of road under Quercus spp., Pinus elliottii, 12 Dec. 2020, M.E. Smith & P.B. Matheny, PBM4533 (TENN-F-075556); ibid., near Goose Lake, 12 Dec. 2020, P.B. Matheny, PBM4542 (TENN-F-075565); Louisiana, St. Landry Parish, Thistlethwaite Wildlife Management Area, Peckham Road, gregarious on soil under Quercus nigra, 17 Jul. 2021, D.P. Lewis, DPL13914 (TENN-F-076539).
Notes: This is the first documentation of Mallocybe fulviceps since it was described from northern Florida by Murrill in 1945. The species is characterized by the small basidiomes (pileus < 30 mm wide, stipe up to 3 mm thick), the often umbonate fulvous pileus, the pale stipe, oblong basidiospores with a mean Q > 2.0, and occurrence under Quercus and Pinus on sandy calcareous soil. A comparison of the types of M. fulviceps, I. pertomentosa, and I. vialis indicate all share the same brown color (7.5YR 4/4 or umber brown with a slight reddish tinge), similar small basidiome size, similar pileus surface, stipe texture, and basidiospore morphology. Inocybe pertomentosa shows a somewhat clustered habit that we also observed in freshly collected material near the type localities. We regard all three as synonymous taxa, yet all have equal priority as they were published in the same study by Murrill (1945). We choose I. fulviceps for priorable purposes because this epithet most accurately describes the species morphologically.
Phylogenetically, M. fulviceps is nested within clade Unicolores with strong support, and nine samples of the species from Florida and Louisiana form a strongly supported clade (Figs 1, 2C). The species is sister to the remainder of the Unicolores clade also with strong support. Mallocybe multispora (documented below) differs from M. fulviceps mainly by the slenderly clavate to subcylindric cheilocystidia. Mallocybe unicolor differs from M. fulviceps by the granulose-scaly pileus surface, presence of dark colored bands of fibrils and scales on the lighter colored stipe, and elongated cheilocystidia.
Descriptions of M. perbrevis by Heim (1931) and Stangl (1989) (both as Inocybe perbrevis) seem most similar to M. fulviceps including the small umbo, small stature, gregarious habit, and association with hardwoods like Populus, Carpinus, and Fagus in Europe. The basidiospores of M. fulviceps (including I. vialis and I. pertomentosa) are narrower than depicted by Heim (1931) but similar to those described by Stangl (1989). Modern molecular comparisons are needed between bona fide collections of M. perbrevis and M. fulviceps.
Mallocybe fulvoumbonata (Murrill) Matheny & Esteve-Rav., Mycologia 112: 106. 2019 [2020].
Basionym: Inocybe fulvi-umbonata Murrill, Quart. J. Florida Acad. Sci. 8: 187. 1945.
Pileus up to 15 mm wide, convex to nearly expanded and with a small but prominent umbo; margin even, entire; surface dry, tomentose, isabelline with a fulvous umbo; context very thin, pallid. Lamellae plane, adnate, medium distant, inserted, pallid [dried specimens dark yellowish brown], fimbriate, broad. Stipe 30 × 2–3 mm, longer than the pileus width, equal, dry, fibrillose, isabelline.
Basidia 26–45 × 7–10 µm, clavate, hyaline or necropigmented, 4-sterigmate. Basidiospores 8–8.7–9(–10.5) × 4.5–5.1–5.5(– 6) µm, smooth, Q (1.50–)1.55–1.76–1.91(–2.00) (n = 52/2), smooth, many phaseoliform or subamygdaliform, at times elliptic, pale brown, with thickened wall, apiculus small and indistinct. Pleurocystidia absent. Cheilocystidia 22–26 × 13–15 µm, reviving poorly, broadly clavate, thin-walled, hyaline (gill edges fimbriate per Murrill), in some sections none observed. Stipitipellis composed of a vesture of loose interwoven hyphae, these cylindric, weakly incrusted, thin-walled, mostly 5–10 µm wide, caulocystidia not observed. Pileipellis a cutis of cylindric hyphae, these cylindric, weakly incrusted, thin-walled, mostly 5–12 µm wide, yellowish brown in mass. Lamellar trama parallel, subhyaline or very pale brown in mass, hyphae cylindric. Clamp connections present.
Distribution: Southeastern USA (Florida).
Habitat: Under Quercus laurifolia. July.
Specimens examined: USA, Florida, Alachua Co., Gainesville, 8 Jul. 1944, W.A. Murrill (holotype FLAS-F-24503, isotype TENN-F-021187).
Notes: Initially, we mistook M. latifolia (documented below) as M. fulvoumbonata, but upon examination of the holotype and isotype, we believe it is more appropriate to maintain them as separate taxa. Thus, despite our efforts to re-collect Murrill species from Gainesville in July, none of our specimens matched M. fulvoumbonata. Therefore, M. fulvoumbonata, known only from the type collection, appears to be best characterized by the lack of any substantial veil remnants over the pileus, the small but prominent umbo, the stipe length longer than the pileus width, the relatively short clavate cheilocystidia, and the noticeably pale brown to light yellow spores that are mostly 8–9 × 5 µm in size.
The other small mallocyboid species described by Murril (viz., M. fulviceps, M. multispora) differ principally by their elongated, darker, narrow spores and/or cheilocystidia with a different morphology. Mallocybe latifolia produces larger basidiomes without a distinct umbo and larger basidiospores (mostly 9–11 × 5.5–6.5 µm) that are more darkly pigmented (yellowish brown). Mallocybe leucothrix also produces larger basidiomes without a distinct umbo, and both the pileus and stipe are overlain with superficial whitish fibrils.
Mallocybe latifolia (E. Ludw.) Matheny & Esteve-Rav., Mycologia 3: 107. 2020 [2019]. Figs 4G–I, 9L, M.
Basionym: Inocybe latifolia E. Ludw., Pilzkompendium (Eching) 4: 153. 2017.
Synonyms: Inocybe acystidiata E. Ludw., Pilzkompendium (Eching) 4: 152. 2017.
Mallocybe acystidiata (E. Ludw.) Matheny & Esteve-Rav., Mycologia 3: 105. 2020 [2019].
Pileus 15–42 mm wide, convex to obtusely conical, expanding to plane in age with an obtuse umbo or depressed at the center; margin inrolled to incurved in youth, later decurved and with the edge remaining inrolled at times; surface dry, tomentose-fibrillose due to superficial thin white covering throughout, the covering wearing away with age, occasionally breaking up into appressed scales or becoming cracked-areolate, never rimose; ground color fulvous or brownish yellow to yellowish brown; context firm, whitish, unchanging where bruised, odor not remarkable. Lamellae adnate to uncinate, close to subcrowded with about 34–40 L and several tiers of lamellulae, medium to somewhat broad; light yellowish brown to light olive brown when young, becoming brown with age; edges whitish-fimbriate. Stipe 30–40 × 2–6 mm, equal, generally not longer than the pileus diameter after pileus expansion; surface dry, usually without a well-developed superior ring-zone (at times a weak ring-zone may be present); cortina white, fugacious; surface white when young due to the presence of superficial silky fibrils throughout, these wearing away, surface becoming coarsely fibrillose or tattered-fibrillose and revealing an isabelline or light yellowish brown ground color with age, base white, not yellow; context solid to hollow, pale brown.
Basidia 28–47 × 7–10 µm, slenderly clavate to subclavate, hyaline or necropigmented, 4-sterigmate. Basidiospores (8–)9– 10–11(–12) × 5.5–5.9–6.5(–7) µm, Q (1.34–)1.50–1.ỔS–1.88(– 2.08) elliptic, subamygdaliform, or subphaseoliform, yellowish brown, with thickened wall, apices often obtuse, apiculus small and indistinct (n = 119/4). Pleurocystidia absent. Cheilocystidia 19–34 × 12–22 µm, clavate to saccate or pyriform, subtending cells often hyphal (not densely articulated), hyaline but many ocher-brown and/or incrusted or appearing with wrinkled walls, thin-walled or with slightly thickened walls, often collapsed in revived dried mounts. Caulocystidia 27–46 × 12– 18 µm, pyriform to clavate or subcylindric, in scattered but dense clusters, often brownish incrusted, thin-walled or with slightly thickened walls. Pileipellis a cutis, ochraceous-tawny in mass, hyphae with thin to slightly thickened walls, incrusted, mostly 6–15 µm wide. Lamellar trama parallel, pale buff in mass, hyphae cylindric, smooth, mostly 5–15 µm wide. Clamp connections present.
Distribution: Eastern and western USA (Arizona, Florida, Maine), southeastern Canada (Quebec), north-central China (Shaanxi), and central Europe (Germany, type), broad and intercontinental.
Habitat: On calcareous soils in mixed forest of Quercus, Pinus, under planted Quercus, Pinus, or in mixed conifer forests including Populus, also under Populus at high elevation (Arizona) and with Populus simonsii (ectomycorrhizal roots) in Shaanxi Province, China; in Europe on calcareous soil under Picea. July– December in eastern USA.
Specimens examined: USA, Florida, Alachua Co., Gainesville, gregarious singly on soil under Pinus, Quercus, in suburban neighborhood, B’nai Israel Synagogue, 3830 NW 16th Blvd, ca. 29.645, -82.327, 9 Dec. 2020, M.E. Smith, MES-3796 (=PBM4535) (TENN-F-075558; FLAS-F-67923); Putnam Co., Melrose, Ordway-Swisher Biological Station, gregarious, often singly, on disturbed soil along roadside under Quercus and Pinus, 12 Dec. 2020, M.E. Smith, PBM4537 (TENN-F-075560); ibid., by west gate entrance, 19 Oct. 2017, M.E. Smith (FLAS-F-61869); Maine, Aroostook Co., Limestone, Aroostook National Wildlife Refuge, Durepo Look Trail, in mixed forest under Picea, Abies, Larix, Betula, and Populus, 10 Sep. 2022, L.V. Kudzma, LVK22088 (pers. herb.); ibid., LVK22089 (pers. herb.).
Notes: Phylogenetic analysis of ITS data obtained from two German type collections (Mallocybe acystidiata and M. latifolia) form a strongly supported monophyletic group with sequences from basidiomes collected under Populus in Arizona and a mixed conifer forest including Populus in Maine, and from ectomycorrhizal root tip sequences of Populus from north-central China (Fig. 2A). In addition, the species has been recently confirmed from Quebec (J. Landry, pers. comm.). No American or Asian names are available for this species-level clade, but there are two equally competing names from Europe (M. acystidiata and M. latifolia) published in the same work (Ludwig 2017) that can be applied to it. We choose M. latifolia over M. acystidiata because cheilocystidia were actually observed in several samples, including a re-examination of the type of M. acystidiata (Bandini, unpubl. data). Overall, the species has a broad intercontinental distribution with a wide range of plant associates. Phylogenetically, M. latifolia is nested within the greater core Mallocybe clade.
Mallocybe latifolia can be distinguished from other eastern North American Mallocybe by the presence of a thin white vesture, occurrence on calcareous soils probably in association with Populus, Pinus, and Picea (and possibly Quercus), the relatively large basidiospores (9–11 × 5.5–6.5 µm), and the cheilocystidia that are collapsed in revived mounts. The species closely resembles M. fibrillosa but lacks the odor (like burnt sugar or honey) of that species. Mallocybe leucothrix also possesses a distinct white vesture but differs from M. latifolia by the smaller basidiospores (8–10 × 4.5–5.5 µm) and phylogenetic affinities with M. leucoloma.
Mallocybe leucothrix Matheny & M.E. Sm., sp. nov. MycoBank MB 847416. Figs 4J, K, 10A, B.
Fig. 10.
Microscopic features of Mallocybe. A. Basidiospores of M. leucothrix (paratype - PBM4531). B. Cheilocystidia of M. leucothrix (paratype - PBM4531). C. Basidiospores of M. luteobasis (paratype – Sayers s.n.). D. Cheilocystidia of M. luteobasis (paratype – PBM4312). E. Basidiospores of M. malenconii (JV4470F). F. Cheilocystidia of M. malenconii (JV4470F). G. Basidiospores of M. montana (holotype). H. Cheilocystidia of M. montana (holotype). I. Basidiospores of M. multispora (isotype). J. Cheilocystidia of M. multispora (isotype). K. Basidiospores of M. praevillosa (FLAS-F-61523). L. Cheilocystidia of M. praevillosa (FLAS-F-61523). M. Caulocystidia of M. praevillosa (PBM4724). N. Basidiospores of M. praevillosa (holotype). Scale bars = 10 µm for spores; 25 µm for cystidia.
Etymology: leucothrix (Gk.), white hairs, in reference to the whitish veil encompassing the basidiomata and close phylogenetic relationship to M. leucoloma.
Typus: USA, Florida, Putnam Co., Ordway-Swisher Biological Station, east of Ashley Prairie near Goose Lake, Melrose, on disturbed soil at side of road under Quercus, Pinus elliottii, 29.705, -81.967, 12 Dec. 2020, M.E. Smith, PBM4541 (holotype TENN-F-075564).
Diagnosis: Distinguished from closely related species by the combination of the whitish veil enclosing medium-sized basidiomata, basidiospores with mean Q values < 2.0, presence of short cylindric to clavate cheilocystidia, and occurrence on calcareous soils with Quercus and Pinus in Florida and Arizona. Forming a unique monophyletic group apart from closest relatives including M. leucoloma, M. subtomentosa, and the undescribed Mallocybe sp. 8.
Pileus 15–55 mm wide, obtusely conical or pulvinate in youth, expanding to broadly convex and plano-convex, at last plane to depressed at the center with age, umbo absent; margin incurved and usually remaining so or decurved when plane; surface dry, appressed tomentose-fibrillose, not at all scaly; color a mixture of various shades of very pale brown, pale brown, or light yellowish brown due to variable coating of a white velipellis, at times with a dull olive tone in areas (10YR 7/3–6/3–6/4; overall near clay color to isabella color where velipellis is exposed); surface dark brown with KOH, fleetingly brown with ammonia; context firm and with a pale yellow tone, confluent with the stipe, unchanging where bruised, odor absent or indistinct. Lamellae adnate to subdecurrent, close; pale olive (5YR 6/3) to grayish olive, becoming yellowish brown (10YR 5/4; clay color), edges indistinctly pallid-fimbriate. Stipe 20–35 × 3–6 mm, equal, often longer than the pileus width (but not always); cortina white and fugacious, not leaving a distinct annular zone; dry, surface overlain with a white vesture of superficial fibrils part of the overall veil, these wearing away revealing a pale brown to yellowish brown ground color, white at the base (not yellow); solid, becoming hollow, pallid with a pale yellow tone like the pileus context.
Basidia 30–35 × 6–15 µm, 4-sterigmate, slenderly clavate, hyaline or necropigmented. Basidiospores (7.5–)8–9.1–10(–11) × 4.5–5.1–5.5 µm, Q (1.50–)1.55–1.78–2.04(–2.08) (n = 41/2), smooth, mostly amygdaliform to somewhat phaseoliform due to a ventral depression, occasionally ovate, apices bluntly pointed, yellowish brown to brownish yellow in KOH, apiculus small and indistinct, wall slightly thickened. Pleurocystidia absent. Cheilocystidia 18–32 × 6–10 µm, cylindric to clavate or short-cylindric to short-clavate, arising from short hyphal segments or articulated hyphae, thin-walled, hyaline, edges of lamellae sterile or nearly so. Caulocystidia present at the extreme apex of the stipe, similar to cheilocystidia. Pileipellis an interwoven cutis, rusty brown to tawny in mass; hyphae cylindric, noticeably incrusted, thin-walled or slightly thick-walled, mostly 5–14 µm wide. Lamellar trama parallel, hyphae mostly 3–19 µm wide, cylindric to inflated, light yellowish brown in mass, thin-walled, smooth. Clamp connections present.
Distribution: Southeastern (Florida) and southwestern USA (Arizona).
Habitat: Scattered to gregarious on karst topography under Quercus virginiana, other Quercus spp., and Pinus elliottii in Florida, also on calcareous soils under Pinus engelmannii and Quercus hypoleucoides in Arizona. August (Arizona) and December (Florida).
Other specimen examined: USA, Florida, Putnam Co., Ordway-Swisher Biological Station, east of Ashley Prairie near Goose Lake, Melrose, 29.705, -81.967, 12 Dec. 2020, C.R. Noffsinger & P.B. Matheny, PBM4531 (TENN-F-075554).
Notes: Mallocybe leucothrix forms a monophyletic group with moderate support based on five samples collected under Quercus and Pinus on calcareous soils in Florida and Arizona. The species is most closely related to an undescribed species that differs ecologically by association with Picea on acidic soils in West Virginia, Quebec, and China. Because of the phylogenetic and ecological differences, we recognize both clades as separate species even though both are united as a strongly supported monophyletic group. Both species are closely related to the intercontinental species M. leucoloma, which to date has been observed in western North America in alpine settings with shrub and dwarf Salix and in conifer forests mixed with Betula and Populus. Several similarities with M. leucoloma include the relatively distinct white veil covering of the basidiomata, white cortina, white stipe base, and the stipe length at times longer than the pileus width. Mallocybe leucoblema can be distinguished from M. leucothrix generally by the more robust size, occurrence on calcareous soils in alpine and montane regions of western North America and Europe, and unique phylogenetic position sister to the Delecta clade.
Mallocybe subtomentosa differs from M. leucothrix by the subsmooth pileus, occurrence on acidic soils with Quercus and/or Pinus, and by phylogenetic position. Mallocybe tomentella (described as new below) differs from M. leucothrix by the bicolorous pileus, presence of a cortinate ring-zone on the stipe, occurrence on acidic soils, and phylogenetic association with members of the M. malenconiigroup.
Mallocybe luteobasis Matheny & M. Kuo, sp. nov. MycoBank MB 847417. Figs 5A–C, 10C, D.
Fig. 5.
Basidiomes of Mallocybe from eastern North America. A. M. luteobasis (MK0611102, photo M. Kuo). B. M. luteobasis (MK07180705, holotype, photo M. Kuo). C. M. luteobasis (G. Sayers s.n., photo G. Sayers). D. M. malenconii (LVK21286, photo L. Kudzma). E. M. montana (PBM4585, photo B. Matheny). F. M. montana (PBM3872, holotype, photo B. Matheny). G. M. montana (PBM4190, photo B. Matheny). H. M. multispora (PBM4717, photo B. Matheny). I. M. multispora (FLAS66616, photo M. Smith). Scale bars = 1 cm.
Etymology: luteobasis (L.), yellow base, in reference to the yellow base of the stipe.
Typus: USA, Illinois, Coles Co., Charleston, Fox Ridge State Park, on soil under Quercus, 18 Jul. 2007, M. Kuo, MK07180705 (holotype TENN-F-073750).
Diagnosis: Distinguished from closely related species by the combination of the medium-sized basidiomata often with large appressed scales, yellow stipe base or yellow basal mycelium, the broad basidiospores with a mean Q value < 2.0, elongate digitiform cheilocystidia, and occurrence on calcareous soils under fagaceous trees. Forming a monophyletic group within the Terrigena grade.
Pileus 20–55 mm wide, convex becoming plano-convex to plane, margin inrolled; surface dry, appressed-squamose to appressed-fibrillose; scales reddish brown, strong brown, or fulvous against a lighter background color, center at times reddish brown; gray or dark brown with KOH; context up to 3 mm thick under the disc, pale yellow, unchanging where bruised, odor none or not distinctive. Lamellae broadly adnate to uncinate, moderately close, lamellulae frequent; pale yellow when young or whitish to brownish yellow or with olivaceous tone, becoming olive-brown (Dresden Brown) with age; edges noticeably fimbriate, white to yellowish. Stipe 25–60 × 3–9 mm, more or less equal or tapered to the base; apex with decurrent lamellar lines; veil cortinate and thick and fibrillose covering the lamellae entirely when young, this becoming a cortinate ring-zone at times but not always; surface dry, fibrillose-scaly or shaggy-fibrillose below the veil, at times fibrils forming bands; fibrils and scales brownish to reddish brown against a dull yellowish ground color; basal mycelium sulphur yellow, especially beneath the soil; context pale yellow, unchanging where bruised, typically yellow at the base when fresh.
Basidia 36–41 × 7–8 µm, 4-sterigmate, slenderly clavate, soon collapsed, becoming necropigmented. Basidiospores (8.5–)9–96–10(–12) × (5–)5.5–56–6(–7) µm, Q (1.50–)1.64– 1.71–1.90(–2.18) (n = 45/3), smooth; elliptic, subphaseoliform, or nearly amygdaliform, at times with a ventral depression; thick-walled, brownish in KOH, apiculus indistinct. Pleurocystidia absent. Cheilocystidia 18–60(–65) × 4–10 µm, many digitiform or irregularly cylindric with a flexuous outline and tapered apices, at times mixed with shorter cylindric cells or apices obtuse or rarely swollen, thin-walled (rarely slightly thickened), hyaline or infrequently ochraceous. Stipitipellis a vesture of superficial hyphae, these dark russet or dark tawny in mass, 5–12 µm wide, weakly incrusted or smooth, thin-walled, caulocystidia not observed; tramal hyphae hyaline, smooth, thin-walled, cylindric. Pileipellis a turf or interwoven cutis of dark russet or dark rusty colored hyphae in mass, these cylindric and mostly 5–12 µm wide, weakly incrusted or smooth, thin-walled. Lamellar trama parallel, pale yellow to subhyaline in mass, hyphae cylindric, many 4–10 µm wide, smooth, thin-walled. Lamellar trama parallel. Clamp connections present.
Distribution: Midwestern (Illinois, Indiana, Kansas) and
southeastern states (Tennessee), USA.
Habitat: On calcareous ground under hardwoods including Quercus, Fagus, Carpinus, and/or Carya. June–September.
Other specimens examined: USA, Illinois, Coles Co., Charleston, Lakeview Park, on ground under Quercus mixed with Carya and Juniperus, 21 Jun. 2011, M. Kuo, MK06211102 (TENN-F-073749); ibid., 29 Jul. 2020, M. Kuo, MK07292005 (herb. Kuo); Marion Co., gregarious under Carya glabra, Ulmus rubra, Juniperus virginina, 7 Jun. 2015, M. Kuo, MK06071503 (TENN-F-074751); Indiana, Parke Co., on soil in deciduous woods, 14 Jul. 2003, M. Kuo, MK07140307 (TENN-F-074752); Kansas, locality unknown, in mixed hardwood forest under Quercus, 7 Aug. 2008, G. Sayers s.n. (TENN-F-063525); Tennessee, Anderson Co., Norris Dam State Park, Clear Creek Trail, on soil in hardwood forest under Quercus, Fagus, Carpinus, Carya, 21 Sep. 2018, P.B. Matheny, PBM4194 (TENN-F-074601); ibid. 8 Aug. 2019, P.B. Matheny & R.A. Swenie, PBM4312 (TENN-F-074884); ibid. 16 Aug. 2020, P.B. Matheny, PBM4437 (TENN-F-075309); ibid. 3 Sep. 2020, P.B. Matheny, PBM4479 (TENN-F-075351); Knox County, William Hastie Natural Area, on soil on karst topography under Quercus, Carya, Pinus virginiana, 5 Jul. 2023, R.A. Swenie, RAS1119 (TENN-F-078399).
Notes: Mallocybe luteobasis is described here as new to accommodate a species recognized by the conspicuous reddish brown to fulvous appressed scales against a lighter background pileus color, dark colored fibrils and scales on the stipe, the yellow stipe base, pale yellow context, and occurrence under hardwoods (Fagales) on calcareous soils in midwestern and southeastern states of the USA. The spores are somewhat wider than all other eastern North American Mallocybe and have an average Q value less than 2.0. An additional distinctive feature of M. luteobasis is the digitiform or subcylindric cheilocystidia that may be elongated. The species could be confused with M. unicolor, but the latter differs from M. luteobasis by the granulose-scaly pileus surface, whitish stipe base, the typically oblong spores, and the differently shaped cheilocystidia (irregularly cylindric to fusiform at times with subcapitate apices). The two species are sympatric and co-occur at the same localities but are distantly related. Mallocybe fulvipes (Cripps et al. 2010) is somewhat similar given the squamulose-fibrillose reddish brown pileus and yellow stipe base, but this species can be distinguished from M. luteobasis by its occurrence in alpine regions with Salix in western North America and Europe and phylogenetic position within the Delecta clade.
Phylogenetically, M. luteobasis represents the first split in the Terrigena grade (Fig. 1) where it is strongly supported as sister to the rest of the core Mallocybe clade. Four specimens sequenced from Illinois (type), Indiana, and Kansas form a strongly supported group. Samples from Tennessee have also been observed.
Smith & Hesler (1968) drew some similarities between Pholiota sola and Inocybe. Pholiotasola is similar to M. luteobasis in outward appearance other than the notably elongated stipe in relation to the pileus width in P. sola. This species was described based on a single collection with the type from Michigan, not Washington D.C. as stated in the protologue. The spores are somewhat narrower compared to M. luteobasis, and chrysocystidia and pleurocystidia were described as present, which would support placement in Pholiota. Smith & Hesler (1968) also noted the dry pileus and the absences of gelatinous tissues and of a germ pore in P. sola, similarly to Mallocybe.
Mallocybe malenconii (R. Heim) Matheny & Esteve-Rav., Mycologia 112: 107. 2019 [2020]. Figs 5D, 10E, F.
Basionym: Inocybe malenconii R. Heim, Encyclopédie Mycol. 1: 163. 1931.
Synonym: Inocybe marmoripes sensu N. Am. auct. p.p.
Pileus 10–25 mm wide, convex to plano-convex or almost plane, never depressed at the center, margin incurved for long durations but not inrolled; surface dry, center decorated with prominent, short, woolly tufts of fibrils that are concolorous with or slightly darker than the rest of the surface, at first simply fibrillose; center dark reddish brown to yellowish red (Argus Brown to Amber Brown (5YR 3/4–4/6), shading to Buckthorn Brown (10YR 5/6–5/8) towards the margin (Sienna color per Heim); context fleshy, firm, pale ocher-pink; odor and taste indistinct. Lamellae adnate or mostly uncinate, moderately close, ventricose but somewhat narrow; cinnamon but becoming much darker with age, edges pallid. Stipe 15–40 × 3–5 mm, irregularly cylindric, usually flexuous, often curved or twisted, equal towards the base; surface dry, in age with darker brown scattered fibrillose tufts; light brownish or paler at the apex and at the base; context fibrous, tough, not putrescent, more or less hollow.
Basidia 20–32 × 6–9 µm, 4-sterigmate, slenderly clavate to subcylindric, hyaline but becoming necropigmented. Basidiospores (9–)9.5–10.7–12 × 4–4.5–5 µm, Q (2.11–)2.20– 2.39–2.75(–2.88) (n = 50/3), smooth; oblong-cylindric, oblong-subphaseoliform, or oblong-amygdaliform (“laceroid”), often with a ventral depression and obtuse to bluntly pointed apices; brownish yellow to pale brown, wall slightly thickened, apiculus small and indistinct. Pleurocystidia absent. Cheilocystidia 17–26 × 10–16(–20) µm, short clavate or short cylindric to sphaeropedunculate or obclavate, thin-walled, hyaline to ochraceous, rarely brownish incrusted; lamellar edges sterile. Caulocystidia similar to cheilocystidia, restricted to the extreme apex of the stipe (possibly just an extension of the hymenium at the extreme stipe apex); superficial hyphae sparse, yellowish brown to ochraceous in mass, cylindric, 6–13 µm wide, weakly incrusted. Pileipellis composed of tufts of trichodermial hyphae, these Tawny to Ochraceous-Tawny in mass, cylindric to inflated and mostly 10–18 µm wide, incrusted to coarsely so, with slightly thickened walls. Lamellar trama parallel; hyphae light yellowish in mass, 10–18 µm wide, smooth, thin-walled. Clamp connections present.
Distribution: Northern regions of eastern and western North America (British Columbia, Maine, New York, Quebec, Washington). Also, northern and central Europe (type), eastern Russia, Korea.
Habitat: On sandy acidic soils under mixture of conifers (Pinus, Picea) and/or Salix and Betula. April–May in the Pacific Northwest, August–September in the northeast USA and southeastern Canada.
Specimens examined: Canada, British Columbia, Cranbrook, on trail to Lloyds Meadows off Crowsnest Highway, 1 100 m elev., 21 May 2002, O. Ceska, 2020521–001 (UBC F19123; image only). Finland, Pohjois-Häme, Saarijärvi, Linnankylä, along margin of road 13, in sandy soil on bank of road near Pinus sylvestris and young Betula pubescens, Salix caprea, and Salix phylicifolia, 18 Aug. 1989, J. Vauras, JV3590F (TURA, WTU); Satakunta, Kankaanpää, Niinisalo, the spring Yskänlähde, on sandy soil near Pinus sylvestris, 24 Jul. 1990, J. Vauras, JV4470F (TURA, WTU); Perä-Pohjanmaa, Rovaniemi rurual commune, Jaatila, Jaatilanvaara, near Savioja, edge of the main road near young Picea abies, Betula, and Salix on sandy soil, 24 Aug. 1991, J. Vauras, JV5824F (TURA, WTU). USA, Maine, Medway, Penobscot Co., Route 11 south of Grindstone Falls Rest Area, on soil along roadside under Quercus, Pinus, 9 Sep. 2022, L.V. Kudzma, LVK22039 (pers. herb.); ibid., LVK22045 (pers. herb.); New York, Essex Co., Bloomingdale, in sandy soil under mixed conifers and hardwoods, 13 Aug. 2021, L.V. Kudzma, LVK21286 (pers. herb.); Washington, Snohomish Co., Point Wells, near Richmond Beach, 2 Apr. 1941, D.E. Stuntz, 948 (WTU).
Other specimen examined (Inocybe subgranulosa): Finland, Tavastia australis, Tamella, Barrskog., på brända sandmarker (Mustiala på Syrjä), 2 Oct. 1892, P Karsten (holotype H 2499).
Notes: The gross morphological description of M. malenconii is taken mainly from Heim (1931, as Inocybe malenconii) but modified to fit the formatting here and supplemented with observations from material collected in the USA. No other previously described North American taxon appears to match this species though it is very closely related to what we now interpret here as M. tomentella described as new below. Several studied European specimens agree morphologically and genetically with North American samples from the Pacific Northwest, New York, and Maine and thus, for the first time, confirm the presence of M. malenconii from North America. It has also been recently confirmed in Quebec (J. Landry, pers. comm.). Where the ecology is known, the species appears to occur on sandy acidic soils.
Mallocybe malenconii resembles forms of Inocybe lacera in outward appearance, and microscopically has similar oblong “laceroid” basidiospores with an average Q value > 2.00. However, the absence of pleurocystidia and presence of necrobasidia easily distinguish the species from I. lacera. The species in a restricted sense is monophyletic with strong support, but references to collections of M. malenconii from China and Spain are very closely related to those of M. subgranulosa (including its type) from Sweden and Finland (Fig. 2A). Mallocybe malenconii differs from M. tomentella morphologically by the narrower “laceroid” shaped spores, however, both were observed to co-occur in the same sandy acidic soil habitats in New York.
Mallocybe malenconii has been reported from Kamchatka in Russia (Peintner & Horak 2002) and Korea (Cho et al. 2021) and thus would have a broad circumboreal distribution, however, Asian samples have yet to be confirmed in the M. malenconii clade in the strict sense. Kauffman (1924) and Stuntz (1940) recognized the species from the Pacific Northwest but under the broadly misapplied name of Inocybe marmoripes. The latter, as interpreted by Kauffman (1924) and Stuntz (1940), actually included two species (M. malenconii and Mallocybe sp. 2 in Fig. 2A). Upon inspection of these materials, Mallocybe sp. 2 was found to differ from M. malenconii genetically and by the longer basidiospores. Note that Inocybe marmoripes is considered a later synonym of M. unicolor (see below).
Mallocybe megalospora differs from M. malenconii by the wider spores and association with Salix and Alnus in Europe (Stangl & Bresinsky 1983). This taxon has not been confirmed from North America. An unpublished sequence (GenBank HQ604786) under this name has been reported from British Columbia, but that sequence represents Mallocybe sp. 2, which appears to be endemic to the Pacific Northwest.
Mallocybe montana Matheny, sp. nov. MycoBank MB 847419. Figs 5E–G, 10G, H.
Etymology: montana (L.), mountain, in reference to occurrence in the southern Appalachian Mountains.
Typus: USA, North Carolina, Haywood Co., Great Smoky Mountains National Park, Big Creek, Baxter Creek Trail, scattered to gregarious on sandy acidic soil in riverbed under hardwoods in a riparian hardwood forest, 518 m elev., 9 Aug. 2012, P.B. Matheny, PBM3872 (holotype TENN-F-067500).
Diagnosis: Characterized by the small to medium-sized basidiomata, finely velutinous pileus, lighter colored stipe, cylindric basidiospores with a mean Q value > 2.0, presence of elongated cheilocystidia that are pale brown in mass in KOH, and occurrence on poor, sandy, acidic soils in Appalachian montane mixed forests. Distinguished phylogenetically as the sister lineage to clades Unicolores, Nothosperma, and Mallocybe.
Pileus 8–35 mm wide, convex at first, occasionally obtusely conical, expanding to broadly convex or nearly plane with age, umbo absent, center slightly depressed with age; margin incurved to decurved, entire; surface dry, velipellis and veil remnants absent, finely tomentose to finely velutinous or matted woolly tomentose under a hand lens, appearing subsmooth to the naked eye; strong brown (7.5YR 4/4) to yellowish brown or dark yellowish brown (10YR 5/6–5/8–6/6–4/4; Prout’s Brown to Dresden Brown), brownish with 5 % KOH; context watery pale brown to olive-yellow when moist, up to several mms thick under the disc, not changing color where bruised; odor noticeable when first cut, nearly acidulous but with an unpleasant component, at times not remarkable; PDAB negative. Lamellae adnate to uncinate, seceding, subdistant with 18–22 L and several tiers of lamellulae; brown to yellowish brown (10YR 5/3–5/4) or dark yellowish brown with age; medium, up to 4 mm deep; edges crenate or nearly so, not white but colored pale brown like the faces. Stipe 14–40 × 2–5 mm at the apex, equal, not bulbous, cortina not observed; surface dry, with scattered fine brown fibrils against a pale brown or pale yellow (buff) to light yellowish brown ground color (2.5Y 7/4, 10YR 6/3–6/4), overall paler than the pileus; context not confluent, pale brown throughout, base encased in sand, basal mycelium white, solid.
Basidia 42–60 × 7–10 µm, 4-sterigmate, slenderly clavate to subcylindric, necropigmented. Basidiospores (10–)11–12.2– 13.5(–14) × (4.5–)5–5.4–6 µm, Q (1.82-)1.92–2.27–2.55(– 2.80) (n = 60/4), smooth, oblong-amygdaliform or cylindric, yellowish brown with thickened walls, apiculus not distinctive. Cheilocystidia 26–74 × 8–16 µm, slenderly clavate or elongate-clavate to somewhat cylindric, arising from short articulated cells, apices often swollen or subcapitate, thin-walled or weakly thickened in places, pale brown in mass, on occasion with fine apical incrustations, necropigmented with age. Pleurocystidia absent. Stipitipellis with clusters of dense short clavate to subcylindric caulocystidia, 27–40 × 8–12 µm, these thin-walled and hyaline; or without caulocystidia, composed of scattered interwoven brownish to ocher-tawny tufts of terminal hyphae similar to pileipellis hyphae; terminal cells cylindric, not particularly cystidioid, pigmented and smooth to incrusted, mostly 8–20 µm wide; with numerous refractive hyphae present in stipe trama. Pileipellis a tangled interwoven trichoderm or short turf, composed of loose chains of hyphae, ocher-tawny in mass in KOH; hyphae cylindric, mostly 8–20 µm wide, walls thin or slightly thickened and often with pale brownish to ochertawny pigment, at times incrusted or coarsely so, terminal cells occasionally cystidioid or differentiated in appearance. Lamellar trama parallel; hyphae pale yellowish in mass, 4–15 µm wide, smooth or weakly incrusted. Clamp connections present.
Distribution: Southeastern USA (North Carolina).
Habitat: Scattered singly or in pairs, often on very sandy acid soil in mixed forests of Quercus, Pinus, Betula, and Tsuga or under hardwoods in sandy riparian areas. July–September.
Other specimens examined: USA, North Carolina, Macon Co., Highlands, Wahalla Road, Blue Valley Road, scattered singly on sandy acid soil on side of dirt road under Pinus strobus, Betula alleghaniensis, Quercus, 760 m elev., 8 Sep. 2018, P.B. Matheny, PBM4190 (TENN-F-074532); ibid., on sandy acid soil on side of dirt road under Quercus, Pinus, 760 m elev., 26 Jul. 2021, R.A. Swenie & P.B. Matheny, PBM4585 (TENN-F-075751); North Carolina, Macon Co., Nantahala National Forest, Rock Gap, Appalachian Trail near Standing Indian Campground, scattered singly on acid soil in mixed forest under Tsuga, Pinus strobus, Quercus, Betula, 885 m elev., 30 Jul. 2021, P.B. Matheny, PBM4614 (TENN-F-075781).
Notes: Mallocybe montana is an unusual species of Mallocybe characterized by the elongated, clavate, pale brown pigmented cheilocystidia, long basidia, and narrow oblong spores. The species is currently only known from the southern Appalachian Mountains at several different localities in western North Carolina where it occurs on acidic and often sandy soils. To the eye, the pileus may seem almost smooth but is velutinous to woolly-tomentose under a hand lens, and no veil remnants have yet been observed. It matches none of the prior descriptions of species made by North American workers, thus the species is described here as new.
Mallocybe montana represents a significant discovery because, together with M. praevillosa (see below), it forms a strongly supported grade (paraphyletic group) from which the remainder of Mallocybe is derived (Figs 1, 2C). Three samples of M. montana collected in different regions of western North Carolina form a strongly supported monophyletic group. Mallocybe multispora is somewhat similar but differs from M. montana by the hyaline or rarely ochraceous cheilocystidia, convex to conical pileus with a small conical or subacute umbo, the more tomentose to scaly pileus covering, occurrence at lower elevations in mixed pine-oak or hardwood forests, and phylogenetic placement in clade Unicolores sister to M. unicolor.
Mallocybe multispora (Murrill) Matheny & Esteve-Rav., Mycologia 112: 107. 2019 [2020]. Figs 5H, I, 10I, J.
Basionym: Inocybe multispora Murrill, Proc. Florida Acad. Sci. 7:122. 1944.
Pileus 7–20 mm wide, convex to conical and often with a distinct (sub)conical or subacute umbo, margin incurved in youth, soon decurved or nearly straight; surface dry, umbo covered with a grayish velipellis, with appressed fibrillose scales at the center, coarsely fibrillose or tomentose towards the margin, not rimose but margin occasionally split; pale isabelline to fulvous or ochraceous tan (yellowish brown or fulvous when dried 10YR 5/6–5/8 or 7.5YR 5/6); context thin, odor sweet [in protologue], “fishy” when cut, or mild. Lamellae adnexed to adnate, moderately close, broad, edges white and fimbriate, yellowish brown to brown. Stipe 15–35 × 1.5–3 mm, subequal above a small bulb or swollen to enlarged, dry, ochraceous-buff, roughened with longitudinal fibrils; context concolorous, not hollow.
Basidia 30–40 × 7–10 µm, 4-sterigmate, slenderly clavate, hyaline or necropigmented. Basidiospores 10–11.3–13(– 14) × 4.5–5.3–6(–6.5) µm, Q 1.82–2.14–2.47(–2.55) (n = 43/2), smooth, yellowish-brown, oblong-elliptic, oblong-subphaseoliform, or oblong-amygdaliform, often with a ventral depression, apices obtuse to bluntly pointed, germ pore absent, thick-walled, apiculus small and indistinct. Pleurocystidia absent. Cheilocystidia 27–55 × 8–15(–20) µm, subcylindric or slenderly clavate with obtuse to subcapitate apices, thin-walled, hyaline (rarely ochraceous), edges of lamellae sterile. Caulocystidia absent, numerous opaque refractive hyphae present among stipe hyphae. Pileipellis a cutis forming trichodermial fascicles, hyphae cylindric to inflated, many 7–12(–20) µm wide and coarsely incrusted and with thickened walls, bright tawny or bright fulvous in KOH. Lamellar trama parallel, yellowish brown in mass, hyphae cylindric and up to 11 µm wide. Clamp connections present.
Distribution: Southern USA (Florida, Oklahoma, Texas).
Habitat: Gregarious on sandy soil, at times pure sand, on calcareous soils (where known) under Quercus, Pinus, palms, or in hardwood forests including Quercus and Carya. June– November.
Other specimens examined: USA, Florida, Alachua Co., Gainesville, gregarious under a palm, 8 Jun. 1938, W.A. Murrill, F17380 (isotype TENN-F-021190, isotype WTU); ibid., Green Acres Park, under Quercus virginiana and Q. nigra, 14 Jun. 2020, M.E. Smith & O. Smith, MES3732 (FLAS-F-66616); Alachua Co., Alachua, Mill Creek Preserve, West Trail, on sandy soil under Pinuspalustris, other Pinus, and Quercus, 6 Jul. 2022, P.B. Matheny, PBM 4717(TENN-F-77391); Martin Co., Jonathan Dickson State Park, on sandy moist pine flatlands with abundant Sabal etonia (Scrub Palmetto) and forbs, 22 Nov. 2017, L. Kaminsky (FLAS-F-61779); Oklahoma, Pontotoc Co., Pontotoc Ridge Nature Preserve, 15.5 miles south of Ada, gregarious on soil in mixed hardwoods under Quercus, Carya, Ulmus, Fraxinus, 21 Sep. 2002, C.L. Ovrebo, CO4248 (CSU); Texas, Newton County, Bleakwood, Lewis properties front lot by state highway 87, on soil in bottomland hardwood forest near Pinus, 36 m elev., 3 Jun. 2020, D.P. Lewis, DPL13581 (TENN-F-0778786).
Notes: This is the first report of Mallocybe multispora since the species was described from northern Florida in the 1940s (Murrill 1944). We confirm, based on morphological comparisons, extant collections from Florida, Oklahoma, and Texas. Of the available names in Mallocybe (under the genus Inocybe) originally described by Murrill, M. multispora matches the modern samples best by virtue of the gregarious habit, small basidiome size, pileus with a conical umbo, pallid stipe, and subcylindric to slenderly clavate cheilocystidia. Murrill also described (from a single collection) the presence of a bulbous stipe base for M. multispora, a feature, however, we did not observe in fresh material. Mallocybe fulviceps is very similar to M. multispora, and closely related to it but differs by the shorter clavate, utriform, or saccate cheilocystidia and phylogenetic position. Mallocybe montana is similar microscopically to M. multispora, but the pileus is not umbonate, the cheilocystidia are often pale brown pigmented, and it occurs on acidic soils in mountainous areas of the Southern Appalachians.
Of European species, M. multispora seems most similar to M. perbrevis reported in association with hardwoods (Heim 1931, Stangl 1989). This species, like M. multispora and M. fulviceps, is also depicted with a small pointed umbo, small stature, and gregarious habit similar to M. multispora. Until direct molecular comparisons can be made with bona fide reference material of M. perbrevis, we prefer to point to the superficial similarities but maintain the autonomy of the two American species. Mallocybe arthrocystis, a pan-north temperate species with oblong or cylindric-shaped spores, associates with Salix in western North America in alpine settings (Cripps et al. 2010). It differs from M. multispora by the short articulated cheilocystidia, bell-shaped pileus, and white lamellae in youth.
Phylogenetically, M. multispora is confirmed with strong support as a closely related sister species to M. unicolor (Figs 1, 2C) in clade Unicolores. Mallocybe unicolor differs from M. multispora and M. fulviceps by the larger basidiomes, pileus without a conical umbo, distinctly granulose-squamulose pileus surface, bands of dark colored fibrils on the stipe, and elongated cheilocystidia.
The ecology of M. multispora is still coming into focus. The subtropical Florida sample was collected in pure sand among pines and palms, whereas our more recent material was collected under oaks. Murrill’s protologue states the type was collected under a palm, a non-ectomycorrhizal plant; however, the Oklahoma material was found in mixed hardwoods under Quercus, Carya, Ulmus, and Fraxinus on sandy soil. The evidence from recent collections suggest that this taxon is likely an ectomycorrhizal associate of Fagales, but we cannot rule out associations with Pinaceae as well.
Mallocybe praevillosa (Murrill) Matheny, comb. nov. MycoBank MB 84723. Figs 6A, 10K–N.
Fig. 6.
Basidiomes of Mallocybe from eastern North America. A. M. praevillosa (PBM4724, photo B. Matheny). B. Mallocybe sp. 8 (PBM4749, photo B. Matheny). C. M. squamosodisca (PBM4307, photo B. Matheny). D. M. squamosodisca (LVK20133, photo L. Kudzma). E. M. subtomentosa (SAT-99-233-01, photo S. Trudell). F. M. subtomentosa (LVK16004, photo L. Kudzma). Scale bars = 1 cm.
Basionym: Lepista praevillosa Murrill, Lloydia 5: 155. 1942. Synonym: Inocybe praevillosa Murrill (Murrill), Mycologia 36: 122. 1944.
Pileus 15–47 mm wide, habit tricholomatoid, convex, broadly convex to conico-convex, expanding to plano-convex with age, not umbonate, margin incurved to decurved; surface dry, villous to fine suede-like smooth over the disc and towards the margin, not rimose, margin entire and at times finely fibrillose, velipellis absent, matt, dull; very pale brown (10YR 7/4) to yellow (2.5Y 7.6) or light yellowish brown (2.5Y 6/4) or Cream-Buff to Chamois or Honey Yellow with Isabella Color tones (2.5Y 5/4–5/6) in places with age, surface negative with 5 % KOH; context thick, white, not changing color where bruised, firm, tough, confluent with the stipe, odor and taste somewhat unpleasant, remaining unpleasant after dried. Lamellae sinuate to uncinate, close to nearly crowded with few tiers of lamellulae, narrow to somewhat broad, brittle, very pale brown to pale brown or light yellowish brown (10YR 7/4–6/3–6/4), edges pallid but indistinctly fimbriate. Stipe 40–80 × 8–11 mm, equal, terete, at times slightly curved, much of the lower part buried in sand; surface dry, rough, scurfy-fibrillose, no veil observed even in a young button; whitish to white throughout, KOH negative on surface; context white, confluent with pileus. Spore print “pale-purplish in mass” per the protologue.
Basidia 31–36 × 7–9 µm, slenderly clavate, 4-spored, hyaline, at times collapsed but none necropigmented. Basidiospores (8– )8.5–9.7–11(–12) × 3.5–4.2–4.5(–5) µm, 1.89–2.30–2.67(–2.75) (n = 62/3), allantoid to oblong-cylindric or oblong-phaseoliform in profile, oblong-cylindric to minimally angular in face view, apices obtusely conical, very pale brown in KOH (noticeably pale), no reaction in Melzer’s, apiculus not distinctive. Pleurocystidia absent. Cheilocystidia 25–61 × 12–22 µm, broadly clavate to broadly fusiform or utriform, at times fusiform, occasionally long-pedicellate, apices often smooth and obtuse but on occasion developing a filiform appendage, thin-walled, hyaline, edges of lamellae sterile. Stipitipellis with protruding cylindric, fusiform, and irregularly cylindric terminal cells 37–66 × 6–8 µm but not appearing in tufts or in a gregarious hymenial formation, these hyaline, more or less thin-walled. Pileipellis a cutis giving rise to trichodermial tufts or interwoven upturned hyphae, thin-walled or slightly thick-walled, 5–12 µm wide, lacking any noticeable incrustations, light yellowish brown or brownish yellow to ocher-tawny in mass (not darkening appreciably in KOH mounts and no exudation of pigment), terminal cells mostly cylindric to slightly clavate. Lamellar trama parallel, dull yellow in mass, hyphae smooth in appearance, thin-walled, up to 10 µm wide. Clamp connections present.
Distribution: Southeastern USA (Florida).
Habitat: Solitary to scattered or gregarious in calcareous sand or sandy soil in high oak-pine forests and sandhill habitat under Pinus palustris and Quercus or under Quercus laurifolia. July– August.
Specimens examined: USA, Florida, Alachua Co., Gainesville, solitary in high Pinus-Quercus woods, 12 Jul. 1939, W.A. Murrill (holotype FLAS-F–19723); ibid., same habitat as above, 6 Jul. 1939, W.A. Murrill (FLAS-F–19703); Alachua Co., Alachua, Mill Creek Preserve, West Trail, on sandy soil under Quercus laurifolia with Pinus palustris in the general vicinity, 6 Jul. 2022, C.R. Noffsinger, PBM4724 (TENN-F-077398); Putnam Co., Ordway-Swisher Biological Station, by Blue Pond, 29.71008 –81.992526, in sandhill habitat under Quercus, Pinus palustris, 28 Aug. 2017, L. Kaminsky & D. Borland (FLAS-F–61523).
Notes: Comparisons of two recent collections from northern Florida with the holotype of Lepista praevillosa indicates they are conspecific with the holotype based on the similar basidiome morphology, ecology, and microscopic features. Blast searches using ITS (GenBank MH211949) and 28S (GenBank MH620294) sequences produced from the modern reference materials were inconclusive and did not provide confident generic placement for this unusual species. Indeed, our rDNA phylogeny placed samples of this species outside Mallocybe among outgroups but with poor support (Supplementary Fig. S3). However, we reextracted DNA from FLAS-F–61523 and PBM4724 and produced longer 28S reads than GenBank MH620294, as well as and partial
rpb1 and rpb2 sequences. In Figs 1 and 2C, one can now see that Lepista praevillosa forms the sister species to the remainder of Mallocybe. Classification of Lepista praevillosa in Mallocybe appears warranted by the rather robust tricholomatoid basidiomes, smooth basidiospores, absence of pleurocystidia, and presence of distinct cheilocystidia. However, the species exhibits some features that deviate from most other species of Mallocybe: (i) the basidia are not necropigmented; (ii) the pileus surface does not darken with application of 5 % KOH; and (iii) the basidiospores are lighter pigmented. One might consider placing L. praevillosa in a separate genus, but this would require description of a new genus to accommodate a single species, so at this time we prefer to classify it in Mallocybe, which is supported by our phylogenetic analyses.
The species shares a few features in common with Tubariomyces, including the allantoid to oblong-cylindric spores and occurrence in sandy soils and sand in oak-pine habitats subject to disturbance by fire (Villarreal et al. 1998, Alvarado et al. 2010, Vizzini et al. 2012, Matheny & Bougher 2017). Species of Cistaceae (genera Lechea and Crocanthemum) do occur in sandhill habitats in northern Florida where one reference specimen was made, so we cannot rule out the possibility of an ectomycorrhizal association with Cistaceae, a feature of some Mediterranean Tubariomyces. However, other key features of Tubariomyces are not found in M. praevillosa, namely, the omphalinoid habit, the broadly attached to decurrent lamellae, and the presence of caulocystidia on the entire length of the stipe.
Index Fungorum mistakenly indicates Inocybe praefarinacea (Murrill) Singer as the current name for I. praevillosa. However, the former is a smooth-spored metuloid-bearing species similar to Inocybe serotina but is phylogenetically allied with the I. metrodii group (Eberhardt et al. 2023).
Our muscarine assay detected its presence in M. praevillosa but at a low relative concentration compared to the only other species of Mallocybe in which we detected the compound, M. sabulosa. The relative muscarine concentration in M. sabulosa was 760 times greater than that found in M. praevillosa.
Mallocybe sp. 8. Figs 6B, 11A, B.
Fig. 11.
Microscopic features of Mallocybe. A. Basidiospores of Mallocybe sp. 8 (PBM4749). B. Basidiospores of Mallocybe sp. (PBM4749). C. Basidiospores of M. squamosodisca (isotype). D. Cheilocystidia of M. squamosodisca (isotype). E. Basidiospores of M. subtomentosa (isotype). F. Cheilocystidia of M. subtomentosa (isotype). G. Cheilocystidia of M. subtomentosa (SAT-99-233-01. H. Basidiospores of M. subtomentosa (SAT-99-233-01). I. Basidiospores of M. tomentella (holotype). J. Cheilocystidia of M. tomentella (holotype). K. Basidiospores of M. tomentosula (RAS123). L. Cheilocystidia of M. tomentosula (RAS123). M. Basidiospores of M. tomentosula (holotype of Inocybe tomentosa - 00775651). Scale bars = 10 µm for spores; 25 µm for cystidia.
Pileus 11–47 mm wide, hemispherical in youth, becoming convex and expanding to nearly plane with age, umbo absent, margin incurved to decurved; surface dry, covered with white, superficial, floccose-tomentose fibrils when young, these relegated to the margin after expansion, not scaly, becoming smooth over the disc; generally fulvous to brown; odor slightly acidulous. Lamellae sinuate-uncinate, close to subcrowded, light olive brown to yellowish brown, edges white-fimbriate. Stipe 25–40 × 3–6 mm, often longer than or equal to the pileus width, equal, terete; surface dry, cortina whitish (not yellow), coarsely fibrillose to lacerate-fibrillose, colored like the pileus, base white mycelioid; context solid, becoming hollow, light yellowish brown.
Basidia 25–34 × 7–9 µm, 4-sterigmate, slenderly clavate, hyaline, necropigmented with age. Basidiospores (8–)8.5–8.9– 9.5(–10.5) × 4.5–5.O–5.5 µm, Q (1.60–)1.70–1.79–1.93(–2.00) (n = 31/1), smooth, subphaseoliform, subamygdaliform, or elliptic, rarely compressed or subangular, apices often bluntly pointed, wall slightly thickened, apiculus small and not very distinct, yellowish brown. Pleurocystidia absent. Cheilocystidia 20–33 × 10–16 µm, mostly clavate, at times utriform or pyriform, hyaline, thin-walled. Pileipellis a cutis of cylindric incrusted hyphae with slightly thickened walls, mostly 6–11 µm wide, russet brown to tawny in mass. Lamellar trama regular; hyphae cylindric, smooth, thin-walled, 4–14 µm wide. Clamp connections present. Distribution: Central Appalachian Mountains of the eastern USA (West Virginia), also China.
Habitat: On acidic soil under Picea rubens in conifer forest, ca. 1 500 m elev. August.
Specimen examined: USA, West Virginia, Pendleton County, Spruce Knob, Whispering Spruce Trail, gregarious to scattered singly on acidic soil under Picea rubens, ca. 1 500 m elev., 8 Aug. 2022, P.B. Matheny, PBM4749 (TENN-F-077511).
Notes: We initially took this single collection as representative of M. subtomentosa in the field but noted the relatively conspicuous white fibrils especially towards the margin of the pilei. Blast searches of sequence data and phylogenetic analyses, however, revealed our West Virginia sample as conspecific with several unidentified samples from China forming a monophyletic group with strong support. The species is very closely related and sister to M. leucothrix (Fig. 2A). Both species, as well as M. leucoloma, which is also closely related, share the relatively distinct white veil covering of the basidiomata, white cortina, white stipe base, and the stipe length often longer than the pileus is wide. Mallocybe leucoloma differs from these by the longer spores and occurrence primarily with Salix and/or Dryas in alpine and montane regions of western North America and Europe. Mallocybe leucothrix associates with Quercus and/or Pinus in Florida and Arizona and occurs in areas with karst topography. By contrast, Mallocybe sp. PBM4947 was observed on acidic soils under Picea but does share a similar spore size and shape with that of M. leucothrix. Mallocybe subtomentosa has a less pronounced initial whitish covering, a subsmooth pileus, and principally occurs with Quercus and Pinus.
As we know the species from only a single sample, we defer to our Asian colleagues to provide a more thorough account and description of this species.
Mallocybe squamosodisca (Peck) Matheny & Kudzma, comb. nov. MycoBank MB 847424. Figs 6C, D, 11C, D.
Basionym: Inocybe squamosodisca Peck, Bull. N.Y. St. Mus. 75: 18. 1904.
Pileus 10–50 mm wide, convex to broadly so, umbo absent, margin incurved and inrolled throughout all stages at least when young, becoming decurved; surface dry, velipellis absent, tomentose-fibrillose, at times breaking into areolate or cracked scales; yellowish brown to ochraceous buff (10YR 5/6–5/8; Buckthorn Brown to Dresden Brown, 6E8–4B4), dark brown with KOH; context whitish with a pale yellow tone (Colonial Buff, 4B4), not confluent with the stipe, rather firm, unchanging where bruised, odor mild or not remarkable. Lamellae adnate to ascending adnexed or sinuate, close with ca. 38–42 L and several tiers of lamellulae, pale yellow (5Y 8/4–7/4, Colonial Buff to Deep Colonial Buff, 5C3) to yellowish brown (10YR 5/6, 6E5); edges even, not fimbriate, more or less concolorous with the faces, medium to broad. Stipe 10–50 × 3–12 mm, short or typically not longer than the pileus width, equal or tapered towards the base, not bulbous, terete; cortina yellowish brown, fugacious; surface dry, nowhere pruinose, heavily silky fibrillose to coarsely fibrillose or villose with scattered tufts of fibrils, becoming lacerate; cortina and/or annular zone buff (5A4-B4); overall brownish yellow (10YR 6/6), somewhat lighter than or nearly concolorous with the pileus but with yellowish brown fibrils; context solid becoming hollow, pale yellow or whitish overall mixed with a pale yellow tone, with a whitish to yellow interior at the base.
Basidia 26–39 × 6–9 µm, (2–)4-spored, slenderly clavate, hyaline to ochraceous. Basidiospores (8–)8.5–9.6–10.5(–12.5) × (4.5–)5–5.3–5.5(–6) µm, Q (1.60-)1.67–1.82–2.00(–2.27) (n = 69/5), smooth, phaseoliform to elliptic or subamygdaliform, at times subcylindric and weakly angular, apiculus indistinct, slightly thick-walled, ochraceous buff to brownish yellow, the occasional long and cylindric spore presumably from 2-spored basidia. Pleurocystidia absent. Cheilocystidia 12–38 × 7–14 µm, short-cylindric, clavate, to obovate, fusiform, or filiform, at times subtended by articulated hyphal cells, thin-walled, hyaline to ochraceous. Pileipellis an irregular or interwoven cutis including tufts of uplifted hyphae, these tawny in mass, cylindric to somewhat inflated, 5–18 µm wide, incrusted and at times coarsely so, thin-walled to slightly thickened. Caulocystidia not observed; superficial hyphae similar to pileipellis hyphae, often coarsely incrusted. Lamellar trama parallel; hyphae ochraceous to pale yellow in mass, cylindric to inflated, 4–19 µm wide. Clamp connections present.
Distribution: Eastern USA (Maine, New York, North Carolina, Tennessee), extending southwards into high elevation oak forests in Costa Rica.
Habitat: On acidic soils under Quercus, Pinus. June–September.
Other specimens examined: Costa Rica, Cartago, Prusia, Parque Prusia, west slope of Volcan Irazu, on acidic soil under Quercus costaricensis, Comarostaphylis, Vaccinium, 20 Jul. 1993, R.E. Halling, REH7036 (NY). USA, Maine, Somerset Co., Appalachian Trail near Pleasant Pond, Caratunk, on soil, 1 Sep. 2020, L.V. Kudzma, LVK20133 (TENN-F-077383); Maine, Penobscot Co., Route 11 south of Grindstone Falls Rest Area, on soil along roadside under Quercus, Pinus, 9 Sep. 2022, L.V. Kudzma, LVK22053 (pers. herb.); North Carolina, Macon Co., Highlands, Cliffside Lake Recreation Area, on acidic soil in mixed woods under Pinus strobus, Tsuga, Quercus, 27 Jul. 2021, P.B. Matheny, PBM4591 (TENN-F-074869); Tennessee, Cumberland County I–40 Rest Area, near Crab Orchard, on soil among bryophytes under Quercus and near planted Pinus, 3 Aug. 2019, P.B. Matheny, PBM4307 (TENN-F-074869); New York, Franklin Co., Paul Smith’s Visitor Interpretive Center, Barnum Brook Trail, 9 Aug. 2021, S. Hopkins, PBM4621 (TENN-F-075791); New York, Adirondack Park, Sacandaga Lake, gregarious under pine trees on lakeshore, 17 Aug. ca. 1903, C.H. Peck (isotype WTU, isotype MICH 11088; image only).
Notes: Inocybe squamosodisca is broadly distributed in the eastern USA and Central America and occurs typically with Quercus and/or Pinus. ITS data from our materials are 98 % similar to sequences of M. substraminipes (fulvipes group A; Cripps et al. 2010) and sequences mislabeled “M. terrigena” (here labeled as Mallocybe sp. 9) from the Pacific Northwest based on blast searches. Phylogenetically, our samples clustered independently in the Delecta clade (Fig. 1) apart from M. substraminipes, M. latispora, and their close relatives (Fig. 2A). Morphologically, our specimens feature stipe context with a pale yellow tone and with white (when very young) or yellow in the stipe base similar to M. substraminipes and allies in fulvipes group A of Cripps et al. (2010). Peck’s protologue made no mention of the color of the stipe context but did describe the pileus context as whitish or yellowish white, consistent with our observation of fresh specimens. In addition, these collections are consistent microscopically with the type, and some of the specimens show a cracked-areolate pileus surface with age. These features, in combination with the longer spores on average and lack of any noticeable odor, serve to distinguish the species from M. fibrillosa.
Smith (1939) considered Inocybe squamosodisca as a possible synonym of I. caesariata sensu Kauffman. This latter name has been applied in various ways by North American authors (Kauffman 1924, Lincoff 1981), but the stipe has generally been recognized as scaly, a feature at odds with I. squamosodisca. Application of the name I. caesariata in Europe is not clear (Stangl 1989). However, the protologue describes the stipe as fibrillose, not scaly. Given the range of materials observed and similarities with the type, including the cracked-areolate pileus surface that develops with age and microscopic similarities, we prefer to recognize this unique phylogenetic entity as Peck’s I. squamosodisca, hence, the recombination in Mallocybe. Specimens from New York and Maine studied by us and sequenced here serve credibly as reference material for this species.
Mallocybe subtomentosa (Peck) Matheny & Kudzma, comb. nov. MycoBank MB 847425. Figs 6E, F, 7A, B, 11E-H.
Fig. 7.
Basidiomes of Mallocybe from North America. A. M. subtomentosa (PBM4703, photo B. Matheny). B. M. subtomentosa (LVK16006, photo L. Kudzma). C. M. tomentella (PBM4690, holotype, photo B. Matheny). D. M. tomentella (SAT-06-228-10, photo S. Trudell). E. M. tomentosula (PBM4138, photo B. Matheny). F. M. tomentosula (HRL0027, photo R. Lebeuf). Scale bars = 1 cm.
Basionym: Inocybe subtomentosa Peck, Ann. Rep. NY St. Mus. 48: 109. 1897 [1895].
Pileus 8–35 mm wide, conical to obtusely conical, margin incurved, umbo absent or rarely low and obtuse; surface dry, not hygrophanous, finely fibrillose, not at all scaly, almost smooth with age, velipellis usually absent; yellowish brown (10YR 5/4–5/6–5/8 or Buckthorn Brown), mixed with some light olive brown tones (2.5Y 5/4 or Isabella Color) or dark yellowish brown (10YR 4/4) at the center, surface brown with 3 % KOH; context pallid with pale yellowish tinge, not changing color where bruised, odor faintly acidulous or not remarkable. Lamellae adnate with slight decurrent tooth, moderately close with several tiers of lamellulae (up to 40 L), light olive buff to pale brown, becoming yellowish brown to dark yellowish brown with age (10YR 5/4–4/4), edges pallid but at most indistinctly fimbriate. Stipe 20–40 × 3–5 mm at apex, longer than pileus width, tapered below or equal, terete; cortina forming thin, silky, cobwebby, white fibrils, fugacious; surface dry, scurfy at extreme apex, elsewhere fibrillose, at times with fine silky white vesture, mostly light yellowish brown (2.5Y 6/4) mixed with light olivaceous tones (Isabella Color) or whitish with dull yellow tones (2.5Y 8/4; Cream-Buff), extreme base with whitish appressed mycelium; context solid becoming hollow, whitish throughout, not yellow at the base.
Basidia 24–33 × 6–9 µm, 4-sterigmate, slenderly clavate, ochraceous or hyaline. Basidiospores 7.5–8.9–9.5(–11) × 4.5–5.05.5־ µm, Q 1.55–1.77–1.90(–2.00) (n = 52/5) smooth, subphaseoliform, subamygdaliform, or elliptic, apices often obtuse, yellowish brown, with slightly thickened wall, apiculus not distinct. Cheilocystidia 13–40 × 7–17 µm, short clavate or pyriform (Opuntia-like), arising from articulated hyphae, occasionally utriform. Pleurocystidia absent. Caulocystidia not observed; stipitipellis composed of a vesture of tangled, sparse, cylindric hyphae, similar to hyphae of the pileipellis, refractive hyphae not observed. Pileipellis a cutis of repent to tangled hyphae, these cylindric and up to 13 µm wide, faintly incrusted with thin or slightly thickened walls, ochraceous-tawny to tawny in mass, refractive hyphae frequent. Lamellar trama parallel, yellowish in mass, hyphae cylindric to inflated and mostly 5–12 µm wide, thin-walled, smooth. Clamp connections present.
Distribution: Northern regions of North America (Alaska, Maine, Massachusetts, New York, New Jersey, Pennsylvania, Quebec), and at higher elevations in the central and southern Appalachian Mountains (North Carolina, West Virginia), and in montane regions of New Mexico and Mexico (Michoacán).
Habitat: On soil (probably acidic) often under Pinus or Pinus mixed with Quercus. June–September.
Other specimens examined: Mexico, Michoacán, Tlalpujahua, Municipio San Felipe del Progresso, Centro Ceremonial Mazahua, on soil in pine forest, 2 889 m elev., 8 Aug. 2018, D.P. Lewis, DPL13020 (TENN-F-074582); ibid., D.P. Lewis, DPL13025 (TENN-F-074575). USA, Maine, Ogunquit Museum of Art, on soil under Pinus strobus, 4 Aug. 2014, L.V. Kudzma, LVK14251 (pers. herb.); Massachusetts, Northbridge, scattered singly on soil among woodchips along roadside in mixed woods including Pinus and Quercus, 26 Sep. 2003, J.C. Slot, PBM2460 (TENN-F-062321); New Jersey, Brendan T. Byrne State Forest near Pakim Pond parking area, on soil under Pinus and Quercus, 15 May 2017, L.V. Kudzma, LVK17005 (pers. herb.); ibid., 17 May 2017, L.V. Kudzma, LVK16004 (TENN-F-077382); ibid., L.V. Kudzma, LVK16006 (pers. herb.); New Mexico, Santa Fe National Forest, Jemez Mountains, Camp Shaver (YMCA), near Battleship Rock, 5 km south of La Cueva, in mixed forest of Pinus ponderosa, Pseudotsuga, Quercus gambelii, Juniperus, 2 060 m elev., 21 Aug. 1999, S.A. Trudell, SAT-99-233-01 (WTU); New York, Rouses Point (near the Canadian border), gregarious or subcaespitose in gravelly soil among fallen leaves, Sep. (day and year not known), C.H. Peck (isotype WTU 018341); Franklin County, Paul Smith’s Visitor Interpretive Center, Barnum Brook Trail, on acid soil in mixed woods under conifers, including Pinus strobus, Betula, Fagus, Populus, 14 Aug. 2021, P.B. Matheny & S. Hopkins, PBM4701 (TENN-F-075838); Franklin County, Hayes Brook Truck Trail, near Paul Smith’s VIC, scattered singly to clustered on acidic sandy soil under conifers including Pinus sylvestris, Abies, 14 Aug. 2021, S. Hopkins & L. Kudzma, PBM4703 (TENN-F-075840); North Carolina, Little Switzerland, Blue Ridge Parkway, on acid soil in mixed forest under Quercus, Pinus, Betula, ca. 1 000 m elev., 22 Sep. 2012, B.P. Looney & M. Sánchez-Garcia, PBM3910 (TENN-F-068440); Tucker Co., Blackwater Falls State Park, Davis, Lindy Point Overlook Trail, on acid soil in hemlock forest under Tsuga, Pinus strobus, Betula, 11 Aug. 2022, R.A. Swenie, PBM4763 (TENN-F-077551).
Notes: Numerous samples of M. subtomentosa from the eastern USA and western regions of North America form a weakly supported monophyletic group sister to M. leucoloma and M. leucothrix, all of which are placed in the Delecta clade within the core Mallocybe clade (Fig. 2A). The species has also been recorded in central Mexico at high elevation, as well as in Quebec (J. Landry, pers. comm.). Of Peck’s available names, this species best fits the protologue of Inocybe subtomentosa. Based on composite data, M. subtomentosa is characterized by the small basidiome size, almost smooth pileus surface, the stipe length longer than the pileus width, the merely fibrillose to scurfy stipe surface, white fugacious cortina, white stipe base, and relatively narrow spores with Q-values less than 2.0. Compared to M. fibrillosa, the pileus of M. subtomentosa is almost smooth, a seemingly distinctive feature. Both M. fibrillosa and M. squamosodisca also have short stipes in relation to the width of the pileus, unlike M. subtomentosa. Mallocybe squamosodisca can be further distinguished from M. subtomentosa by the pale yellow tone to the stipe context and usually yellowish stipe base. Mallocybe subtomentosa was described with a white mycelioid base, which we observe here consistently among the collections examined.
Mallocybe leucoloma and M. leucothrix can be distinguished from M. subtomentosa by the presence of a superficial covering of white tissue when young that remains on the pileus margin or stipe with age (Cripps et al. 2010; see also under M. leucothrix). As in M. subtomentosa, the cortina is white and often copious and the odor faint or not noticeable. In North America, M. leucoloma is distributed in western states better known from alpine areas of the Rockies, but the species also occurs in montane conifer forests of Wyoming and Washington.
Stuntz’s application of the name Inocybe subdecurrens (Stuntz 1947) could fit our concept of M. subtomentosa given the ample white cortina, stipe length longer than the pileus width, similar spore size, and the short articulated cheilocystidia. A single collection (Stz. 604) was cited under Alnus and Acer in lowland Washington state. Stuntz described the pileus as campanulate to plane with a small obtuse umbo and densely appressed lanuginose forming squamules toward the margin. This last feature deviates from all the material we have observed and is more consistent with M. fibrillosa, of which we consider I. subdecurrens a synonym, or Stz. 604 could represent a nonalpine M. leucoloma.
We observed many single nucleotide polymorphic sites (SNPs) across samples of M. subtomentosa in our concatenated alignment at ITS (5), 28S (4), rpb1 (8), and rpb2 (30) loci. Taxon sampling was uneven across the four loci sequenced, but the relatively consistent occurrence of SNPs at all four loci may suggest some degree of hybridization among divergent populations within M. subtomentosa or with closely related species.
Mallocybe tomentella Matheny & Kudzma, sp. nov. MycoBank MB 847421. Figs 7C, D, 11I, J.
Etymology: tomentella (L.), somewhat hairy, in reference to the fibrillose-tomentose pileus.
Typus: USA, New York, Franklin Co., Bloomingdale, Bloomingdale Bog, scattered to gregarious, singly or in pairs, on very sandy acidic soil along roadside under mixture of trees including Picea, Abies, Pinus strobus, Larix, Populus, Betula, Alnus, 490 m elev., 13 Aug. 2021, S. Hopkins & P.B. Matheny, PBM4690 (holotype TENN-F-075826).
Diagnosis: Pileus generally tomentose-fibrillose, at times bicolorous due to accumulation of cobwebby whitish fibrils at the margin; odor absent; stipe often with a distinct apical cortinate ring-zone, context light yellowish brown to isabelline; differing from Mallocybe malenconii by the shorter, wider, and differently shaped basidiospores, these mostly 8–10.5 × 4.5–5.5 µm (Q value < 2.00); cheilocystidia < 40 µm long, hyaline; on poor acidic sandy soils under Picea, Populus.
Pileus 12–40 mm wide, pulvinate with an incurved margin at first, becoming convex, soon plane, at times depressed at the center and with somewhat raised margins, with or without a low obtuse umbo; surface dry, velipellis absent, generally tomentose-fibrillose, exceptionally forming minute floccose scales; often bicolorous (at least when fresh) with the center yellowish brown (10YR 5/8; Buckthorn Brown) and the margin light yellowish brown (10YR 6/4) or noticeably pale due to the accumulation of radially, cobwebby, whitish fibrils; with age the center may be dark brown or umbrinous but also ranging to fulvous or almost so throughout; surface dark brown with 5 % KOH; context dull dingy pale brown, not yellow, unchanging color where bruised, PDAB negative, odor absent. Lamellae adnate to weakly subdecurrent, close with several tiers of lamellulae, narrow to medium, not broad; pale brown to brown (10YR 6/3–5/3), yellowish brown with age (10YR 5/4), at times with olivaceous tones. Stipe 25–45 × 2–6 mm, equal or at times with a slightly swollen base, cortina whitish and often forming a distinct apical or superior cortinate ring-zone, veil remnants appendiculate along the margin of the pileus at times; surface dry, nowhere pruinose, fibrillose to coarsely so or tattered fibrillose, the superficial fibrils silky and pallid against the light yellowish brown to isabelline ground color; context soon hollow, colored like the stipe ground color.
Basidia 24–30 × 7–9 µm µm, 4-sterigmate, slenderly clavate to subcylindric, hyaline or necropigmented. Basidiospores 8–9.0–10.5(–11) × 4.5–5.0–5.5 µm, Q (1.48-)1.60–l.8l–2.00(–2.09) (n = 76/3), elliptic to subphaseoliform or subamygdaliform, at times suboblong, not at all or rarely subangular, apices obtuse or bluntly pointed, brownish yellow to yellowish brown, with a slightly thickened wall. Pleurocystidia absent. Cheilocystida 20–34 × 11–16 µm, mostly clavate to broadly so (not short-clavate) to saccate or spheropedunculate, thin-walled, hyaline. Caulocystidia not observed. Pileipellis a cutis of cylindric hyphae, these often coarsely incrusted and with slightly thickened walls and 7–17 µm wide, russet brown in mass. Lamellar trama parallel; hyphae pale yellow in mass, cylindric, thin-walled, mostly 4–12 µm wide. Clamp connections present.
Distribution: Northern regions of eastern and western North America (New York, Quebec, Alberta).
Habitat: On poor, sandy, acidic soils under Picea, Populus tremuloides, or in mixed forests including these trees. August.
Other specimens examined: Canada, Alberta, Division No. 14, Bighorn Recreation Trail, Robb Road/Cold Creek Road, near Hinton, on soil in Picea-Populus tremuloides forest, 1 160 m elev., 16 Aug. 2010, S.A. Trudell, SAT0622810 (TENN-F-071587). USA, New York, Franklin Co., Bloomingdale, Bloomingdale Bog, scattered to gregarious, singly or in pairs, on very sandy acidic soil along roadside under mixture of trees including Picea, Abies, Pinus strobus, Larix, Populus, Betula, Alnus, 490 m elev., 13 Aug. 2021, S. Hopkins & P.B. Matheny, PBM4694 (TENN-F-075831).
Notes: Mallocybe tomentella is characterized namely by the white cobwebby fibrils covering the pileus margin and darker disc when fresh, depressed pileus center usually with a small umbo, long incurved pileus, presence of a cortinate ring-zone, basidiospores with Q value < 2.00 on average, and putative association with Picea and possibly Populus on acidic soils. Our phylogenetic analyses support a broad northerly distribution between Alberta on one hand and New York and Quebec on the other [the latter as Inocybe sp. RL8 (GenBank MN992187)].
Both M. malenconii and M. subgranulosa can be distinguished from M. tomentella by the fine scaly pilei and narrow laceroid or minimally angular basidiospores with higher Q values. Support values for the clade of M. tomentella are only moderate, but together the samples form a robustly supported monophyletic group with M. subgranulosa and two orphaned samples of M. malenconii from China and Spain (Fig. 2A). However, given the differences in morphology, including the pileus surface structure (not granulose) and basidiospore morphology (not subangular and “laceroid”), we prefer to recognize M. tomentella as a distinct taxon. Further samples from Asia, Europe, and North America, including more genetic data, will be needed to ascertain whether the group might be a complex of entities surrounding M. subgranulosa. This M. subgranulosa “complex” is sister to M. malenconii s.str. with strong support.
A similar species, M. tomentosula, is presented below. The two species share the presence of cortinate ring-zone and non-laceroid basidiospores with mean Q values < 2.00. However, M. tomentosula differs from M. tomentella by occurring on limestone soils with Quercus and/or Pinus strobus. It also differs from M. tomentella by the darker colored pileus, phenology, and phylogenetic position where it occurs in a well-supported group containing M. heimii, M. velutina, M. depressa, and M. errata (viz., the Heimii clade; Fig. 1).
Mallocybe tomentosula Matheny & Esteve-Rav., Mycologia 112: 109. 2019 [2020]. Figs 7E, F, 11K-M.
Basionym: Inocybe tomentosa Ellis & Everh., J. Mycol. 5: 26. 1889, nom. illegit., Art. 53.1, non Inocybe tomentosa Quél. 1888.
Pileus 12–45 mm wide, convex or obtusely conical in youth, soon expanding to plano-convex or plane with age, umbo generally absent, center occasionally depressed, margin incurved at first and remaining slightly so when expanded or decurved with age; surface dry, velipellis absent, densely fibrillose-tomentose, at times with few scattered appressed scale-like aggregates of fibrils, not rimose; yellowish brown or fulvous (10YR 5/6–5/8) to strong brown or nearly rusty brown (7.5YR 4/4) with age, after drying specimens noticeably umbrinous; context whitish to olivaceous or with olivaceous streaks, odor none. Lamellae adnate or uncinate, close with 40–50 L and several tiers of lamellulae; light yellowish brown to light olive brown (2.5Y 6/4–5/4–5/6) to rusty brown with age, edges even and not appearing fimbriate, medium (2–4 mm deep). Stipe 10–35 × 3–5 mm, equal, cylindric, not bulbous; surface cortinate in youth, cortina composed of fine whitish silky fibrils, often leaving a superior annular zone; nowhere pruinose, dry, fibrillose to coarsely so, nowhere scaly, colored more or less like the pileus or with isabelline areas; base not yellow.
Basidia 24–36 × 7–8 µm, 4-sterigmate, slenderly clavate to cylindrico-clavate, hyaline or necropigmented. Basidiospores (8–)8.5–9.4–10.5(–11) × (4.5–)5–5.4–6(–6.5) µm, Q (1.50-) 1.61–1.74–1.98(–2.04) (n = 71/3), smooth, subamygdaliform to elliptic, at times subphaseoliform due to a ventral depression, apices bluntly pointed or obtuse, yellowish brown, wall slightly thickened, apiculus small and not very distinct. Pleurocystidia absent. Cheilocystidia 14–34 × 8–13 µm, short-cylindric to short-clavate or pyriform, arising from articulated hyphal cells, hyaline or brownish incrusted, thin-walled, edges of lamellae becoming pigmented with age. Pileipellis a cutis of regularly to somewhat tangled and coarsely incrusted hyphae, russet or dark tawny in mass, hyphae cylindric and mostly 7–17 µm wide, more or less thin-walled; tramal hyphae light yellowish brown in mass, smooth, thin-walled. Caulocystidia not observed. Lamellar trama parallel, hyaline in mass, hyphae mostly 4–12 µm wide, smooth, thin-walled. Clamp connections present.
Distribution: Eastern North America (Quebec, New Jersey, Tennessee), including Mexico (Tlaxcala).
Habitat: On calcareous soils in Tennessee and Mexico, under Quercus, Pinus strobus or P. cembroides (plantation), and/or Juniperus; type recorded near Picea abies in New Jersey, soil conditions unknown. April and November (southern range), July–September (northern range).
Specimens examined: Canada, Quebec, Saint-Alban, under Pinus strobus sandy soil, 20 Sep. 2006, R. Lebeuf, HRL0027 (TENN-F-071134); USA, New Jersey, Gloucester, Newfield, in grass around Norway spruce, Sep. 1888 (no day and no collector cited) [holotype NY 00775649, 00775650, 0075656, 00775651 (isotype ex Barnard College)]; Tennessee, Knox County, Knoxville, Ijams Nature Center, on dry gravelly soil under Quercus montana and Juniperus virginianus at a limestone quarry, ca. 300 m elev., 17 Apr. 2016, R.A. 5wenie, RAS123 (TENN-F-071659); ibid., 11 Nov. 2017, P.B. Matheny, PBM4138 (TENN-F-071134).
Notes: Mallocybe tomentosula is most closely related to the European species M. heimii, the South Asian species M. velutina (Saba & Khalid 2020), and the East Asian M. depressa from China (Mao et al. 2022) (Fig. 2B). This strongly supported assemblage forms a sister group to M. errata from Thailand. Mallocybe fuscomarginata is superficially similar to M. tomentosula in that both may be characterized by the presence of brownish incrusted cheilocystidia, the cigar brown colored pileus, and the veil in M. fuscomarginata that at times forms a thin ring-zone (Jacobbson & Larsson 2012). However, both the spores and cystidia of M. fuscomarginata are larger than in M. tomentosula, and the gill edges of the latter are not noticeably dark brown. The two species are distantly related (Fig. 2B).
Mallocybe tomentosula has a wide geographic distribution ranging from Quebec to central Mexico (Meza-Meneses et al. 2016), where it associates with species of Pinus subg. Strobus and Quercus on limestone soils where known. The ecology, in combination with the medium sized basidiomes, the presence of a superior cortinate ring-zone, spores mostly 8.5–10.5 × 5–6 µm, and the short articulated cheilocystidia that become brownish with age, serve to distinguish it from other eastern North American Mallocybe. In addition, the phenology of M. tomentosula is unusual in that it has been recorded as early as April in Tennessee on multiple occasions, and again in November. In Quebec the species was recorded with Quercus, Populus, Salix, and/or Picea in city parks and forested areas between July and September (J. Landry, pers. comm.). The soil conditions of the Canadian samples are not known.
Matheny et al. (2020) introduced Mallocybe tomentosula Matheny & Esteve-Rav. as a nom. nov. for I. tomentosa Ellis & Everh., an illegitimate name due to the publication of the same binomial, I. tomentosa Quél. during the prior year. The ecology of the type is not clear with the mention only that the species occurred near planted Norway spruce in New Jersey.
The holotype of I. tomentosa comprises four parts on a single sheet, all from the same original gathering, one of which is an exisotype, since rejoined with the holotype, from Barnard College. Attempts to produce molecular annotations by Sanger sequencing (775651 and 775656) failed due to very poor quality and heterogeneous nature of the reads. All four elements resemble each other and are consistently light yellowish brown overall. We could not glean any data regarding the cheilocystidia morphology from the holotype, but the spore shape and size are consistent with our other observations of what we interpret as this species. Unpublished observations of the type of I. tomentosa by D.E. Stuntz in Feb. 1964 featured clavate to spheropedunculate cheilocystidia 28–36 × 12–14 µm in size. This feature is also consistent with our other studied specimens. Thus, the presence of a cortinate ringzone, probable association with Quercus and Pinus (and possibly other plants), spore and cystidium morphology, and geography (New Jersey) are all consistent with sequenced samples studied by us from Quebec and Tennessee.
Kauffman (1924) and Smith (1939) considered I. tomentosa (our M. tomentosula) as synonymous with I. subdecurrens, however, we recognize the latter as a later synonym of Mallocybe fibrillosa. Our interpretation of M. fibrillosa differs from M. tomentosula in that M. fibrillosa lacks a cortinate ring-zone and tends to feature a (subtly) sweet odor. Phylogenetically, the two species are distantly related (see commentary below).
Mallocybe unicolor (Peck) Matheny & Esteve-Rav., Mycologia 112: 109. 2019 [2020]. Figs 8A–D, 12A–F.
Fig. 8.
Basidiomes of Mallocybe unicolor from eastern North America (all photos by B. Matheny). A. PBM4013. B. PBM3794. C. PBM1481. D. PBM4451. Scale bars = 1 cm.
Fig. 12.
Microscopic features of Mallocybe unicolor. A. Basidiospores (isotype). B. Cheilocystidia (isotype). C. Basidiospores (isotype of Inocybe marmoripes). D. Cheilocystidia (isotype of I. marmoripes). E. Basidiospores (isotype of I. lorillardiana). F. Cheilocystidia (isotype of I. lorillardiana). Scale bars = 10 µm for spores; 25 µm for cystidia.
Basionym: Inocybe unicolor Peck, Ann. Rep. NY St. Mus. 50: 104. 1897.
Synonyms: Inocybe lorillardiana Murrill, Mycologia 3: 101. 1911. Inocybe marmoripes G.F. Atk., Am. J. Bot. 5: 213. 1918.
Inocybe caesariata sensu N. Am. auct. p.p., non Kauffman 1924.
Illustrations: Lincoff (1981, as I. caesariata); Phillips (2010, as I. caesariata).
Pileus 15–50 mm wide, deeply convex when young to obtusely conical or parabolic to conical, becoming subcampanulate and finally plane, an obtuse umbo sometimes present, margin incurved to decurved; surface dry, granulose due to very fine recurved or appressed squamules (resembling Cystoderma), at times velvety in appearance, margin entire (not rimose), dark brown with 3–5 % KOH (pale or light brown with 10 % NH4OH); the scales dark yellowish brown or strong brown (Cinnamon Brown) at the center (10YR 4/4–7.5YR 4/4) against a yellowish brown or fulvous ground color (10YR 5/6–5/8; Buckthorn Brown), on occasion faded to light yellowish brown; context up to 3 mm thick beneath the disc, whitish, not confluent with stipe; odor and taste not remarkable. Lamellae narrowly adnate to uncinate, moderately close with 24–30 L and several tiers of lamellulae; cream colored or pale yellow when young (2.5 Y7/4), becoming light olive brown or isabelline (2.5Y 5/4) to dark yellowish brown (10YR 4/4) with an olive tinge or olive brown (2.5Y 4/4); equal to subventricose, up to 6 mm deep; edges white and fimbriate. Stipe 30–50 × 2–7 mm, often longer than the pileus diameter, terete or compressed, usually equal but occasionally slightly swollen or tapered at the base; cortina yellowish brown, fugacious; surface dry, densely fibrillose when very young but soon breaking up into yellowish brown or cinnamon brown squamules, these recurved at times, against a pale yellowish brown ground color (contrasting with the darker colored scales), dark brown with 5 % KOH; apex of stipe finely fibrillose, not pruinose; context solid becoming hollow but with a tough cortex, dingy whitish or with slight yellowish tinge, unchanging color where bruised or exposed. Context negative with guaiac and PDAB.
Basidia 28–38 × 7–10 µm, 4-sterigmate, clavate hyaline but becoming necropigmented. Basidiospores (8.5–)9.0–9.9–11.5(– 12) × (4.0–)4.5–5.0–5.5(–6.0) µm, Q 1.64–1.97–2.33(–2.44) (n = 72/4), smooth, oblong-elliptic to oblong-subamygdaliform or oblong-subphaseoliform, at times with a ventral depression, apices obtuse or bluntly pointed, thick-walled to slightly thick-walled, brownish yellow (Ochraceous-Buff), apiculus small and indistinct. Pleurocystidia absent. Cheilocystidia 32–65 × 9–13 µm, irregularly cylindric, at times strangulated, or fusiform, narrowly utriform to lageniform, apices often swollen or indistinctly subcapitate, thin-walled, hyaline, edges of lamellae sterile. Caulocystidia not observed, superficial hyphae on stipe forming a trichoderm or interwoven layer of cylindric hyphae, these 4–10 µm wide, ocher-tawny in mass, end cells undifferentiated or at times flexuous or lageniform; subtending hyphae pale yellow brown to hyaline in mass, up to 14 µm wide, with walls that appear smooth. Pileipellis a cutis giving rise to fascicles of trichodermial elements that are ocher-tawny in mass; hyphae cylindric to inflated and up to 18 µm wide, incrusted, with slightly thickened walls; hyphae of subpellis up to 25 µm wide. Lamellar trama parallel, pale yellowish brown to hyaline in mass, hyphae cylindric and up to 12 µm wide, rusty colored refractive hyphae present. Clamp connections present.
Distribution: Throughout eastern North America. Common.
Habitat: Scattered to gregarious, at times forming troops, singly or in small groups on calcareous soil under Quercus, Carya, and Carpinus, or under planted Quercus or Tilia, at times on lawns in grass, generally in oak-hickory forests, or mixed mesic forests including Quercus and Tsuga on acidic soils. June–October.
Specimens examined: USA, Illinois, Coles Co., Charleston, First and Harrison, gregarious in grass under Quercus, 18 Jun. 2015, M. Kuo, MK06181501 (TENN-F-073747); Coles Co., Charleston, Fox Ridge State Park, picnic area, on gravelly soil under Quercus, Carya, 28 Aug. 2014, M. Kuo, MK08281401 (TENN-F-074753); ibid., 28 Aug. 2014, M. Kuo, MK08281401 (TENN-F-074753); Iowa, Linn County, Mount Vernon, Palisades-Kepler State Park, on karst topography in hardwood forest, 15 Jul. 2020, S. DeLong-Duhon, iNAT53190985 (TENN-F-076529); Missouri, Taney Co., Mark Twain National Forest, Ozark Mountains, Coy Bald Trail at Hercules Glen, on soil in campground along creek in under Quercus, Carya, Juglans, 4 Jul. 1999, P.B. Matheny, PBM1481 (WTU); New York, Menands, on clay soil, July, C.H. Peck s.n. (isotype of I. unicolor, WTU); Bronx Co., New York Botanical Garden, on soil in lawn under Quercus, Fagus, Acer, 20 Sep. 1987, R.E. Halling, REH5532 (WTU); New York City, in front of museum building, caespitose in grass under Carya, 25 Jul. 1916, W.A. Murrill s.n. (WTU 63030); Tompkins Co., near Glenwood (suburb of Ithaca), west of Cayuga Lake, solitary to subcaespitose on ground in woods, July, B. Walker, Atk24275 (isotype of I. marmoripes, WTU); North Carolina, Haywood Co., Great Smoky Mountains National Park, Baxter Creek Trail, 11 Sep. 2004, P.B. Matheny, PBM2645 (TENN-F-062476); ibid., 7 Jul. 2015, P.B. Matheny, PBM3997 (TENN-F-70346); Macon Co., Highlands Biological Research Station, under Pinus Quercus, and Rhododendron on acid soil, 29 Jul. 2021, C.R. Noffsinger, PBM4604 (TENN-F-075771); Yancey Co., Burnsville, Carolina Hemlocks campground, in hemlock dominant forest under Quecus, Tsuga, Rhododendron on acid soil, 20 Aug. 2020, P.B. Matheny, PBM4452 (TENN-F-075323); Tennessee, Anderson Co., Norris Dam State Park, Clear Creek Trail, under Quercus, Carpinus, Fagus, Carya, 11 Oct. 2009, P.B. Matheny, PBM3331 (TENN-F-063892); Blount Co., Great Smoky Mountains National Park, Schoolhouse Gap Trail, 8 Jun. 2012, C.C. Braaten, CCB48 (TENN-F-067079); ibid., 17 Jul. 2019, R.A. Swenie & S.R. Warwick, PBM4301 (TENN-F-074863); Cocke Co., Great Smoky Mountains National Park, Low Gap Trail, 10 Oct. 2010, M.G. Wood, MGW869 (TENN-F-065333); Cumberland Co., Interstate 40 rest area between exits 324–325, on ground under Quercus, 23 Jul. 2018, P.B. Matheny, PBM4167 (TENN-F-074483); Knox Co., west Knoxville, residential area, on soil in grass under planted Quercus phellos, 29 Jul. 2008, P.B. Matheny, PBM2974 (TENN-F-062732 – muscarine assay); Knox Co., University of Tennessee campus, the Hill, in lawn on soil under planted Tilia americana, 7 Aug. 2009, P.B. Matheny, PBM3322 (TENN-F-063887); Knox Co., Sharp’s Ridge Memorial Park, on soil under hardwoods, 2 Aug. 2022, R.A. Swenie, RAS1007 (TENN-F-077502); Sevier Co., Great Smoky Mountains National Park, Alum Cave Bluffs Trail, 11 Aug. 2005, E.B. Lickey (TENN-F-061152); Virginia, Shenandoah National Park, north park entrance, Dickey Ridge Trail, 600 m elev., on clay soil in Oak-Hickory forest (Quercus, Carya, Juglans, Liriodendron, Robinia), 22 Jun. 2002, P.B. Matheny & E.C. Durman, PBM2320 (WTU).
Notes: Mallocybe unicolor is easy to recognize in the field due to the granulose-scaly pileus, the dark colored fibrillose scales on the stipe, the dull olivaceous to brownish lamellae, and habitat typically under oaks. The species is also characterized by the elongated cheilocystidia and oblong spores with mean Q-values ranging mostly between 1.90 and 2.25. Mallocybe unicolor is widespread in eastern North America and common in Oak-Hickory forests and urban habitats in lawns under planted Quercus, Carya, and Tilia, typically on karst topography. To a lesser extent it has been found in mixed mesic Hemlock (Tsuga) forests including Quercus and Betula on acidic soils characterized by presence of Rhododendron. It is unknown at this time if these ecological differences correspond to divergent populations.
Because the species is so common throughout eastern North America, it is not surprising it has been described as new independently by several early 20th century taxonomists. Under incandescent light the scales of M. unicolor could be interpreted as “ferrugineous” as described by Murrill for Inocybe lorillardiana based on examination of authentic material gathered by Murrill from the type locality. Bessette & Fatto (1998) presented a thorough study of the holotype of I. marmoripes consistent with our evaluation of the isotype at WTU. The basidiospore dimensions of I. marmoripes fall within range of the collections studied here, although the mean Q value (2.25) is longer than those of some other collections (1.86–1.89), but similar to the Virginia material (2.12) and the type of M. unicolor (2.09). At present, DNA sequences from numerous samples of M. unicolor form a cohesive strongly supported monophyletic group (Fig. 2C), but some separation was noted for two samples from New York and Missouri (REH5532 and PBM1481) characterized by the shorter Q values (1.86–1.89). Murrill’s collection of I. lorillardiana also shares the shorter spores (mean Q 1.86). However, based on current sampling, we regard these differences as indicative of population-level variability based on current sampling. Additional collections, backed by further genetic data, are needed to determine if there is any taxonomic significance to the shorter-spored variants consistent with I. lorillardiana, and whether these might be correlated with edaphic factors.
Kauffman (1924) reported I. marmoripes from Maryland and Washington, however, his description of the cheilocystidia as clavate is not in concordance with the type. Kauffman’s concept of I. marmoripes was a broad one including M. malenconii and the undescribed Mallocybe sp. 2 from Oregon and British Columbia (the latter reported as M. malenconii var. megalospora by its GenBank authors). Stuntz (1940) applied the name I. marmoripes to what we interpret as M. malenconii, which can be distinguished from M. unicolor by the smaller basidiomes (pileus up to 20 mm wide), short clavate cheilocystidia, and slightly narrower and somewhat angular basidiospores (9–12 × 4–5 µm) similar to those of Inocybe lacera in appearance.
The name Inocybe caesariata (Fr.) P. Karst. (non Kauffman) has been widely applied to M. unicolor by Hesler (1936), Lincoff (1981), Phillips (2010), and Roberts & Evans (2011). Use of the name I. caesariata by Kauffman (1924) in our opinion corresponds to M. fibrillosa Peck.
One MyCoPortal record (CMMF002038) from Quebec is misidentified as I. unicolor. The photograph of the specimens resembles those of M. subtomentosa.
A liquid chromatography-tandem mass spectrometry assay by Kosentka et al. (2013) did not detect muscarine in sample TENN-F-062732 (PBM2974).
Extralimital taxa
Mallocybe callichroa (E. Horak) Matheny, comb. nov. MycoBank MB 847422.
Basionym: Inocybe callichroa E. Horak, Westerdijk Biodiversity Series 16: 76. 2018.
Notes: Inocybe callichroa (Horak 2018) bears many features indicative of Mallocybe: the overall ocher-brown coloration of the basidiomes, the slenderly clavate basidia, the smooth slenderly phaseoliform basidiospores with an average Q value at or near 2.00, the absence of pleurocystidia, the presence of cheilocystidia and clamp connections, and a cutis to trichoderm type of pileipellis. Furthermore, the pileus was described as velutinous to minutely squamulose and the odor as indistinct. All of these features are consistent with Mallocybe. Horak, however, did note that KOH failed to darken the pileus surface, and no explicit statement of the presence of necrobasidia was made. Despite this, and given the overall combination of features above, placement in Mallocybe seems most warranted, hence the new combination above. The species is a Nothofagus associate, and the first species of Mallocybe described from New Zealand.
Key to Eastern North American species of Mallocybe
1a. Pileus granulose-scaly and stipe with bands of dark colored fibrillose-scales against a lighter background.........................................M. unicolor
1b. Pileus and stipe not as above.................................................................................................................................................................................2
2a. Basidiospores oblong, mean Q > 2.0.................................................................................................................................................................3
2b. Basidiospores not oblong, mean Q < 2.0.................................................................................................................................................................6
3a. Basidiomes robust (mature stipe 8–10 mm wide), flesh tough, lamellae brittle, pileus surface not darkening with application of KOH solution, basidiospores pale brown in KOH.................................................................................................................................................................M. praevillosa
3b. Basidiomes not robust (mature stipe < 8 mm wide), flesh soft and lamellae soft, pileus surface darkening with KOH, basidiospores yellowish brown in KOH.................................................................................................................................................................4
4a. Pileus convex to plano-convex at first and not umbonate; cheilocystidia short-clavate, pyriform to short-cylindric (< 30 µm long); on acidic soil in northern forests.................................................................................................................................................................M. malenconii
4b. Pileus convex to broadly convex and not umbonate; cheilocystidia elongated (> 30 µm long); on acidic soil in southern Appalachian montane forests.................................................................................................................................................................M. montana
4c. Pileus conical at first and umbonate, cheilocystidia differently shaped than above (> 30 µm long); on calcareous soil, northern Florida in oak-pine forests.................................................................................................................................................................5
5a. Cheilocystida subcylindric or slenderly clavate with obtuse to subcapitate apices.................................................................................................................................................................M. multispora
5b. Cheilocystidia clavate (not slenderly so), utriform, saccate, and/or obovate.................................................................................................................................................................M. fulviceps
6a. Stipe base yellow and/or stipe context with pale yellow tone.................................................................................................................................................................7
6b. Stipe base white and stipe context without a yellow tone.................................................................................................................................................................8
7a. Basidiospores 6–6.5 µm wide, on karst topography under oak-hickory.................................................................................................................................................................M. luteobasis
7b. Basidiospores 5–5.5 µm wide, on acid soils under oaks, pine, ericaceous trees and/or shrubs, or other conifers (Pseudotsuga) ................................................................................................................................................................. M. squamosodisca
8a. Stipe with a distinct cortinate ring-zone.................................................................................................................................................................9
8b. Stipe without a distinct cortinate ring-zone.................................................................................................................................................................10
9a. Pileus brown to dark brown, not bicolorous, in areas with limestone under Quercus or Pinus.................................................................................................................................................................M. tomentosula
9b. Pileus two-toned or bicolorous with a brown disc and whitish margin due to heavy accumulation of superficial fibrils, on acidic soils under Picea or in mixed forests including Picea.................................................................................................................................................................M. tomentella
10a. Pileus subsmooth in age and often without an umbo, on acidic soils.................................................................................................................................................................11
10b. Pileus tomentose-fibrillose to squamulose, at times umbonate, soil type various.................................................................................................................................................................12
11a. Under Quercus and/or Pinus.................................................................................................................................................................M. subtomentosa
11b. Underd Picea.................................................................................................................................................................Mallocybe sp. PBM4749
12a. On acidic soils in northern and alpine regions, odor often sweet.................................................................................................................................................................M. fibrillosa
12b. On calcareous soils in various regions (Maine, Florida, Arizona) but not alpine; odor not remarkable 13 13a. Pileus not umbonate, with a distinct hairy white vesture; basidiospores 8–10 × 4.5–5.5 µm, yellowish brown in KOH; cheilocystidia < 12 µm wide.................................................................................................................................................................M. leucothrix
13b. Pileus at most weakly umbonate, with a distinct hairy white vesture; basidiospores 9–11 × 5.5–6.5 µm, yellowish brown in KOH; cheilocysatidia > 12 µm wide.................................................................................................................................................................M. latifolia
13c. Pileus with a small but prominent umbo, without a distinct hairy white vesture; basidiospores 8–9 × 4.5–5.5 µm, very pale brown to light yellow in KOH; cheilocystidia > 12 µm wide.................................................................................................................................................................M. fulvoumbonata
Unclarified species of Mallocybe from North America, Asia, and Australasia
Nine insufficiently known species, seven from western North America, one from eastern North America, and one from New Zealand, are recognized from one or few collections or are known only from environmental samples. These species will be documented taxonomically elsewhere pending evaluation of additional data.
Mallocybe sp. 1 was recovered from three environmental root system samples of Dryas integrifolia in the Alaskan arctic by Timling et al. (2012); the species is very closely related to M. delecta (syn. M. crassivelata), a European species found in hardwood and conifer forests (Crous et al. 2020). We are unaware of any collections associated with Mallocybe sp. 1 at this point. Inocybe marmoripes sensu D.E. Stuntz (Stuntz 1940) undoubtedly represents Mallocybe sp. 2, which we have documented from Oregon and confirmed from British Columbia (see discussion above under M. unicolor). Sufficient collections are on-hand eventually to describe this species. Mallocybe sp. 3 (PBM1615) is known from a single collection under montane conifers in Washington state and is the sister species to the northern European species M. arthrocystis (FIG. 2B) with strong support. Mallocybe sp. 4 (PBM2290) is yet another likely undescribed species from Washington state that is also in the Arthrocystis clade, but it is known only from one collection. Mallocybe sp. 5 (JFA13285, PBM1922, SDA470) is likewise an independent lineage collected under montane conifers from Washington state and is sister to M. fuscomarginata from Europe; we intend to present a formal description of this species at a later date. Mallocybe sp. 6 (ADP060305, PBM1444) is yet another montane conifer-associate found in Washington state; it is strongly supported in a sister position to all other species in the Fuscomarginata clade and will be formally described in forthcoming works. Mallocybe sp. 7 represents an unclarified species with an omphalinoid habit from New Zealand found in likely association with Nothofagus. It does not appear to match any of the previously described species attributed to Mallocybe from this region (Horak 2018); it is known from a single collection at this time. Mallocybe sp. 8 is represented by one known American collection studied by us from West Virginia and several samples from China and Quebec (the latter communicated by J. Landry); this species is probably undescribed. Mallocybe sp. 9 is known from several samples from the Pacific Northwest to which the name Inocybe terrigena has been misapplied; this entity forms a paraphyletic group in our analyses but deserves further scrutiny. Lastly, the status of some collections documented from Australia by Matheny & Bougher (2017) related to M. isabellina, M. subflavospora, and M. pyrrhopoda await further revision.
Excluded Eastern North American species attributed to Mallocybe
Inocybe angustispora Bessette & Fatto, Mycotaxon 66: 123. 1998.
Synonym: Inocybe taedophilia Murrill, Proc. Florida Acad. Sci. 7: 122. 1944.
Both I. angustispora and I. taedophila are later synonyms of Cortinarius aureifolius Peck (Matheny 2003, Matheny & Ammirati 2003). Gene sequences of 28S, rpb1, and rpb2 have been produced from the holotype of I. angustispora.
Inocybeferruginosa A.H. Sm., Pap. Mich. Acad. Sci. 24: 93. 1939.
Ammirati (1972) synonymized I. ferruginosa and Cortinarius uliginosus var. nauseosus with Cortinarius uliginosus. However, Niskanen (2014) combined I. ferruginosa in Cortinarius. An ITS sequence has been produced from the holotype, which supports assignment of the species in Cortinarius.
Inocybe weberi Murrill, Proc. Florida Acad. Sci. 7: 123. 1944.
The punctate elliptic to subamygdaliform basidiospores (8–9 × 5–5.5 µm), in combination with the yellowish lamellae and presence of anthraquinone interhyphal pigment deposits, suggest the type is synonymous with Cortinarius croceus (Matheny 2003).
DISCUSSION
This study is the first systematic revision of Mallocybe as it occurs in eastern North America. We used four different gene regions for phylogenetic analyses and considered taxon sampling across the globe. Our intent was to revise first those species that occur in eastern North America and generate a useful and predictive infrageneric systematic arrangement. To facilitate stable application of names, we have produced sequenced reference specimens for seven species described in historical works by Peck, Ellis & Everhart, and Murrill. Some authors have had success with molecular annotation of types and other historical collections of Inocybe (Cripps et al. 2010, Matheny & Swenie 2018, Matheny & Kudzma 2019). However, the process to do so must take steps to avoid contamination from non-target fungi (e.g., Aspergillus) and laboratory aerosols and equipment. These problems can be mitigated with careful laboratory procedures and taxon-specific primers. Even with these approaches, the success rate is still low for collections made by Murrill from northern Florida in the 1930s and 1940s (Looney 2014). This is probably due to poor preservation technique by the original collector, the age of the specimens, or degradation of DNA over time. Moreover, some of Murrill’s types are scanty or composed of single basidiomes. In addition, recent studies by Eberhardt et al. (2022, 2023) were only able to produce partial molecular annotations for one of six species of Inocybaceae described by Peck more than 100 years ago, and only a few Inocybaceae described by Murrill could be partially annotated. While epitypification is a useful tool to ultimately clarify and stabilize species recognition (Hyde & Zhang 2008), we avoided this procedure because interpretation of North American types attributable to Mallocybe could be accomplished based on morphology and ecology, most often in comparison to modern reference materials collected by us at or near type localities. As a consequence, several unused names attributable to Mallocybe have been resurrected in this study based on our interpretations of the types (M. fibrillosa, M. subtomentosa, M. squamosodisca, and M. unicolor of Peck; M. fulvoumbonata, M. fulviceps, and M. multispora of Murrill; and M. tomentosula, a replacement name based on the type of Inocybe tomentosa Ellis & Everh.). In addition, we were able to resuscitate the Murrill name Lepista praevillosa and recombine it in Mallocybe, which was discovered as the sister species to all other Mallocybe. Despite resurrecting several old names, we still detected undescribed lineages to which no prior names could be applied and described four of those as new – M. leucothrix, M. luteobasis, M. montana, and M. tomentella. We are also aware of additional species from eastern North America (e.g., Mallocybe sp. 8) that remain unclarified or possibly undescribed but are not yet sufficiently documented.
Our study also recovered three strongly supported clades within Mallocybe that could correspond to subgenera (clades Mallocybe, Nothosperma, and Unicolores) but await formal description pending efforts at revision of additional taxa. Clade Mallocybe contains the bulk of known Mallocybe species, and these primarily originate from temperate regions of the northern hemisphere and are often characterized by presence of short cheilocystidia. Clade Nothosperma contains species known from Australasia (Australia, New Zealand, New Guinea) and Malaysia; most of these species too are primarily characterized by the presence of short cheilocystidia. Clade Unicolores contains six species, three of which are endemic to eastern North America and characterized by spores with mean Q values near or greater than 2.00 and often elongated cheilocystidia (> 50 µm in length) (Hu et al. 2023).
One challenge we encountered during this work was the phylogenetic placement of the recently described western and southern African tropical species M. africana (Aignon et al. 2021). We have been aware of this species for some time (see Matheny et al. 2009 where it was treated as “I. microdulcamara nom. prov.”) based on nuclear ribosomal DNA sequences only and found the species to cluster with another Old World tropical lineage from south Asia, M. errata, with strong support (Matheny et al. 2009). Aignon et al. (2021) were able to generate rpb2 data from recent materials, but our phylogenetic analysis of RNA polymerase II data only (not shown) placed M. africana in a sister position to all other species of Mallocybe. Unfortunately, gene sampling across Mallocybe is uneven (e.g., rpb2 data could not be generated for M. errata, and we could not independently obtain new rpb2 and rpb1 sequences from M. africana either), so we cannot exclude the possibility that uneven gene and taxon sampling could impact the placement of this unusual species, or that existing data provide conflicting phylogenetic signal. Thus, we treat M. africana as incertae sedis within Mallocybe. Additional specimens and loci (e.g., rpb1) of M. africana will need to be produced and re-analyzed, and data produced from M. althoffiae by the senior author but analyzed by Aignon et al. (2021) should be discarded as artifacts (Matheny et al. 2020).
Our rDNA phylogeny (Supplementary Fig. S3) was ambiguous about the placement of Mallocybe praevillosa, where it clustered with weak support among outgroup taxa. However, individual analyses of rpb1 and rpb2 (Supplementary Figs S1, S2) and analyses of the combined data (Figs 1, 2), strongly supported M. praevillosa as sister to all other Mallocybe in this work. Mallocybe praevillosa possesses some character states unlike other Mallocybe in that (i) the pileus surface did not darken with KOH, (ii) the basidia were not necropigmented, and (iii) the flesh of the basidiomes was tough and the lamellae brittle. In addition to these features, the basidiospores were found to be noticeably pale, but this trait has been noted in other species (e.g., M. subflavospora, M. fulvoumbonata). Furthermore, M. praevillosa was the only eastern North American sample for which we detected muscarine. One might consider accommodation of M. praevillosa in a separate (new) genus apart from Mallocybe due to the unique combination of traits highlighted above, but we decided against this decision owing to taxonomic redundancy (viz, establishing a monotypic genus), the few specimens studied, and the fact that the species forms a strongly supported clade with the rest of Mallocybe.
This work also recapitulates and highlights some significant evolutionary and ecological findings. Hu et al. (2023) demonstrated that the presence of elongated cheilocystidia was a shared ancestral state in Mallocybe. Our study reinforces this result even with the discoveries of M. montana and M. praevillosa. The shift to short-clavate or short-pyriform cystidia may have occurred in the most recent common ancestor of clades Mallocybe and Nothosperma or perhaps independently in these groups. We also find it notable that species of the Montana and Praevillosa lineages, as well as those in clade Unicolores, exhibit relative narrow ranges of endemism, and all either originate in eastern North America or east Asia. The Australasian species in clade Nothosperma likewise exhibit narrow-range endemism either restricted to Australia or New Zealand. By contrast, many species in the core Mallocybe clade exhibit broad intercontinental geographic distributions as noted previously by Cripps et al. (2010).
Our work also provides a multigene phylogenetic framework to continue studies and revision of additional taxa from other parts of the world. For example, we detected seven species-level lineages that occur in western North American conifer forests that are likely undescribed. In addition, further attention is necessary to clarify some Australasian species of Mallocybe (Matheny & Bougher 2017).
Detection of the secondary metabolite muscarine varies within Mallocybe. Here we report the non-detection of muscarine in nine of the 11 species sampled. Muscarine was detected at relatively high amounts in two distantly related species (M. sabulosa from Australia and M. praevillosa from Florida). Kosentka et al. (2013) and Stijve et al. (1985) also reported the lack of detectable amounts of muscarine from M. unicolor and M. terrigena, respectively. The evolutionary and ecological significance of the absence and sporadic presence of muscarine across the genus are poorly understood at this time. Future efforts are needed to assess the relative concentrations of the toxin among multiple samples within species and confirm the taxonomy and earlier reports of muscarine-containing Inocybe attributable to Mallocybe today (Stijve et al. 1985, Gurevich & Nezdoiminogo 1992), including species M. agardhii, I. caesariata, I. dulcamara, and M. malenconii (Kosentka et al. 2013).
Acknowledgments
This study was supported by grants from the Daniel E. Stuntz Memorial Foundation, the Tennessee Herbarium Hesler Endowment Fund, and the National Science Foundation (DEB–2030779). The authors thank Shannon Adams, Joe Ammirati, Christine Braaten, Cathy Cripps, Sarah DeLong-Duhon, Django Grootmyers, Alicia Hobbs, Sigrid Jakob, Jacob Kalichman, Hailee Korotkin, Jacques Landry, Danny Miller, Dick Morrison, and Aaron Wolfenbarger for their laboratory assistance or sharing materials for this study. Marcos Caiafa, Rosanne Healy, Susan Hopkins, and Caro Willis kindly assisted with field work. We also thank Jerry Cooper and Noah Siegel for sharing specimen-voucher information and ITS data for New Zealand material, and acknowledge the contribution of ITS and morphological data kindly shared by Christiane Baschien, Ditte Bandini, and Ursula Eberhardt from Erhard Ludwig’s herbarium materials. The authors are also indebted to Ellen Larsson, who shared ITS data from type collections made by Petter Karsten. We appreciate the support from herbarium directors and staff at FLAS, H, NY, TENN, and WTU and the provision of loans for this study. We also acknowledge support from Katarina Jones and Hector Castro for their assistance at the Biological Small Molecular Mass Spectometry Core at the University of Tennessee (RRID: SCR_021368). Comments from two reviews improved an earlier draft version.
Conflict of interest: The authors declare that there is no conflict of interest.
Supplementary material
ML rpb1 gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
ML rpb2 gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
ML ITS+28S rDNA gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
ML rpb1 gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
ML rpb2 gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
ML ITS+28S rDNA gene phylogeny of Mallocybe. Numbers above or below branches indicate bootstrap proportions > 50 %.
