A macroconidial synanamorph of Kendrickiella phycomyces (Pezizomycotina incertae sedis)

Abstract

A macroconidial synanamorph, namely a phragmosporous phialidic morph of Kendrickiella phycomyces (Pezizomycotina incertae sedis), was newly observed in authentic cultures isolated from the Kitora and Takamatsuzuka Tumuli in Japan. The synanamorph was sparsely produced throughout of the colonies on PDA after a few days at room temperature in cultures revived from lyophiles or in streak cultures, both derived from germinated Kendrickiella-type aseptate microconidia. After 1-2 wk, the microconidial synanamorph (the Kendrickiella-type synanamorph) and creeping hyphae completely overgrew the macroconidial morph produced on the colony surface. This sparsely produced morph appears to be a common cultural character in K. phycomyces with pleomorphic conidiation. The morphology of the macroconidial morph is described and the taxonomy of K. phycomyces is briefly reviewed and discussed.

Three morphologically similar hyphomycete genera, namely Leptographium Lagerb. & Melin, Verticicladiella S. Hughes (now treated as a synonym of Leptographium; Wingfield, 1985) and Phialocephala W.B. Kendr. were once treated as the Leptographium complex (Kendrick, 1961). These genera were distinguished by their modes of conidiogenesis (i.e., annellidic, sympodial, and phialidic modes, respectively). Leptographium is now classified in the Ophiostomatales and Phialocephala in the Helotiales (Seifert et al., 2011). A bristle-like hyphomycete producing penicillate conidiophores with a slimy phialoconidial head, Phialocephala phycomyces (Auersw.) W.B. Kendr., was described by Kendrick (1964) based on isolates from French Guiana and Congo that matched the type collection of Hantzschia phycomyces Auersw. from Germany (Auerswald, 1862; Wollenweber and Stapp, 1928). Kendrickiella phycomyces (Auersw.) K. Jacobs & M.J. Wingf. was subsequently proposed as a new combination for P. phycomyces by Jacobs et al. (2001) in the monotypic Kendrickiella K. Jacobs & M.J. Wingf., which is related to the Eurotiales based on 28S rRNA gene analysis. Based on 18S, 28S (D1/D2 region) and ITS-5.8S rRNA genes, Kiyuna et al. (2012) further investigated the phylogeny of K. phycomyces using many isolates from the Kitora and Takamatsuzuka Tumuli in Japan and two BCCM/MUCL strains (https://bccm.belspo.be/MUCL-catalogue-search) examined by Kendrick (1964) and Jacobs et al. (2001). Kiyuna et al. (2012) treated K. phycomyces as Pezizomycotina incertae sedis, rather than the Eurotiales.

It has long been believed that K. phycomyces produces only a macronematous penicillate morph (the Kendrickiella-type synanamorph), designated in this paper as the microconidial synanamorph (abbrev. as microconidial morph; Gräfenhan et al. (2011) for microconidial and macroconidial synanamorphs). Our observations, however, reveal an additional macroconidial synanamorph (abbrev. as macroconidial morph), namely a phragmosporous phialidic morph visible in the early stages of culture growth. In this paper, the morphology of a macroconidial morph is documented with microphotographs and the taxonomy of K. phycomyces, now recognized to have pleomorphic conidiation (Okada et al., 1995), is briefly reviewed and discussed.

Representative strains of Kendrickiella phycomyces JCM 18027 (= K4910-1, stone ceiling of the Kitora Tumulus, Japan), JCM 28336 (= K5906-2-1, stone wall of the Kitora Tumulus), JCM 18031 (= T61114-1-1, sealed stone of the Takamatsuzuka Tumulus, Japan) were checked for the presence of a macroconidial morph (for details of the strains, see Kiyuna et al. (2012) and the online catalogue of the Japan Collection of Microorganisms (RIKEN BRC-JCM; https://jcm.brc.riken.jp/en/catalogue_e). These strains were revived from lyophiles (i.e., lyophilized microconidia) on potato dextrose agar plates (PDA; Nissui Pharmaceutical Co., Ltd., Tokyo, Japan). Morphology was observed initially using a DF microscope (Olympus, Tokyo, Japan). The habit was photographed by DS-5M/DS-Fi1 digital cameras (Nikon, Tokyo, Japan) attached to an OPTIPHOT microscope with a M Plan 10x SLWD long working distance objective lens (Nikon). For microphotography, a BIOPHOT microscope with differential interference contrast (DIC) optics (Nikon) or an ORTHOPLAN microscope with phase contrast (PC) optics (Leitz/Leica, Wetzlar, Germany) were equipped with the same Nikon digital cameras. Some photographs were prepared as composite images (CI), in which appropriate parts of different photographs were manually combined to form a single image. Some photographs in Figs. 1, 2 were shown in black and white (BW) to eliminate bluish or greenish color artifacts.

Fig. 1 - Microconidial synanamorph of K. phycomyces JCM 18027 on PDA. A Habit. Microconidia accumulating in a hyaline/white drop at the head of conidiophores. B, D Reddish-brown thick-walled conidiophore with a hyaline complex fan-shaped conidiogenous structure. C Hyaline, ellipsoidal, non-septate, and smooth-walled microconidia. E, F Acropleurogenously arranged phialides. G Verticillate three phialides. B-G DIC; E CI; B, C, E-G BW. Bars A 1 mm; B 100 μm; C-G 10 μm.

Fig. 2 - Macroconidial (A-H) and microconidial (F) synanamorphs of K. phycomyces JCM 18027 on PDA. A, B, F Habit of macroconidial and microconidial morphs. The first conidium (arrows) in the macroconidial morph was produced from a hyaline simple phialide, and the conidia were accumulating in slimy drops (arrowheads) on phialides. Microconidial morph (stars) with brown robust conidiophores were later produced abundantly. C-E Monophialides producing hyaline macroconidia with 0-3 septa; phialides sometimes separated from short conidiophores with a septum (arrowhead in D). G, H Fresh (G) or germinating (H) macroconidia with 0-3(-6) septa (arrowheads). Macroconidia usually had a truncate base. C, E, G, H DIC; D PC; C, D, F-H CI; D, E BW. Bars A-E, G, H 10 μm; F 50 μm.

The term “anamorph” (Turland et al., 2025) was accepted following the rationale of Seifert (2013) and Kirschner (2019), and we used “synanamorph” in this paper instead of “synasexual morph” (Hernández-Restrepo et al., 2017). For the herbarium and culture collection acronyms, see Index Herbariorum (https://sweetgum.nybg.org/science/ih/) and WDCM Culture Collections Information Worldwide (https://ccinfo.wdcm.org/), respectively.

Kendrickiella phycomyces (Auersw.) K. Jacobs & M.J. Wingf. [as ‘phycomycoides’], in Jacobs, Wingfield, Jacobs & Wingfield, Can. J. Bot. 79: 113 (2001).

Synonymy:

≡ Hantzschia phycomyces Auersw. (basionym), Hedwigia 2: 60 (1862); Hantzschia Auersw. 1862 nom. rej., non Hantzschia Grunow 1877 (Bacillariophyceae).

≡ Scopularia phycomyces (Auersw.) Goid., Boll. Staz. Pat. veg. Roma, N.S. 15: 156 (1935); Scopularia Preuss 1851 nom. illeg., non Scopularia Lindl. 1834 (Orchidaceae).

For these and other synonyms, see Kendrick (1964), Shaw and Hubert (1952), and Species Fungorum (2026b).

Type: GERMANY, Dresden, on an oak barrel in a cellar, Dec 1860, leg. C.A. Hantzsch (holotype B 70 0113012 (Supplementary Fig. S1), ex Herb. Hantzsch, = Rabenhorst's Fungi europaei #441 (exsiccata); R. Jarling, personal communication). At least, the following duplicates from the exsiccata (isotype) exist: B 70 0113013 (exsiccata, ex Herb. O. Pazschke; R. Jarling, personal communication); BPI 996925 (exsiccata; MycoPortal, 2026a); CUP (exsiccata; MycoPortal, 2026b); DAOM 34098 (slides from CUP; Kendrick, 1964; MycoPortal, 2026c); S F45962 (exsiccata, ex Herb. Sydow) and S F45963 (exsiccata, ex Herb. H. Rehm) (MycoPortal, 2026c). On the duplicates in WIS and G (exsiccatae), Shaw and Hubert (1952) and Kendrick (1964) respectively mentioned their existence.

Classification: Pezizomycotina incertae sedis (Kiyuna et al., 2012).

Teleomorph: Unknown.

Substrate, location, and collection: Growing on an oak wood barrel (Germany; type collection); isolated as a contaminant culture from a polypore (French Guiana, St. Laurant du Maroni; DAOM 63734, herbarium material); soil (Belgian Congo; IMI 58648 and DAOM 63899, herbarium materials); isolated as a contaminant of Ganoderma sp. (Ecuador; MUCL 38565, live isolate); a barrel in a cellar (USA, NJ, Newfield; DAOM 34392, herbarium material); stone walls of the Kitora and Takamatsuzuka Tumuli (Japan; JCM 18027, JCM 18031, and JCM 28336, live isolates) (Auerswald, 1862; Jacobs et al., 2001; Kendrick, 1964; Kiyuna et al., 2012; MycoPortal, 2026c; Shaw and Hubert, 1952).

Microconidial synanamorph (Fig. 1) and cultural properties: Although Kendrick (1964), Jacobs et al. (2001), and Kiyuna et al. (2012) described this morph well, we found the conidiogenous cells to be arranged acropleurogenously (Fig. 1E, F; in DAOM 34098 (K. Seifert, personal communication); see also Fig. 3 in Kendrick (1964), Fig. 5g in Kiyuna et al. (2012), and Plate 63C in Seifert et al. (2011)) as well as in whorls (Fig. 1G; namely with 2 or 3 verticillate phialides per branch as described by Jacobs et al. (2001) and Kiyuna et al. (2012)). Colonies grew faster at 25 °C than 20 °C on PDA. For colony photographs of the Japanese isolates, see the JCM online catalogue.

Macroconidial synanamorph (Fig. 2): The morph was sparsely produced throughout of the colonies on PDA after a few days at room temperature (ca. 25 °C) in cultures revived from lyophiles or in streak cultures, both originally derived from germinated Kendrickiella-type aseptate microconidia. After 1-2 wk, the macroconidial morph produced on the colony surface was completely overgrown by the abundantly produced microconidial morph and creeping hyphae. Conidiophores were sparsely produced, mostly with integrated conidiogenous cells, or sometimes separated from the cells by a septum, very short, unbranched, thin-walled, and hyaline. Conidiogenous cells were monophialidic, subulate, slender, non-septate, thin-walled, hyaline, 35-60 μm long, 3-4 μm wide at the base, and with an inconspicuous collarette at the tip. Macroconidia were much larger than the microconidia, cylindrical, with 0-3(-6) septa, rounded at the apex, usually with a truncate base, hyaline, (11-)16.5-26(-51) × (4-)4.5-6.5 μm, and accumulating in a wet drop containing around 10 conidia at the tip of phialides.

Strains examined: JCM 18027, JCM 18031, and JCM 28336.

Notes: For the typification of Hantzschia phycomyces, Shaw and Hubert (1952) mentioned that the “type” is Rabenhorst's Fungi europaei #441. However, there is some confusion around the correct type designation as follows: 1) Kendrick (1964) and Jacobs et al. (2001) respectively treated Auerswald's collection (exsiccata) in CUP and G as the “type” and DAOM 34098 (slides made from the CUP exsiccata) as the lectotype; 2) Species Fungorum (2026a) treated Tab. XI (figure plate) in Auerswald (1862) as the type in the “typification details”. Because the information on the original material of H. phycomyces is clearly available from Auerswald (1862) as “Nr. 441 der Fungi Europaei” (exsiccata) and exsiccatae have been used for effective publication and typification before 1953 (cf., Art. 30.4, Art. 30 Note 1, and “exsiccata” in the Appendix VII in the Vienna Code (McNeill et al., 2006); Art. 30.8 and Art. 30 Note 2 in the Madrid Code (Turland et al., 2025)), the specimen in Germany, B 70 0113012 (exsiccata, Supplementary Fig. S1; cf., Tab. XI in Auerswald (1862) and Tab. III, G in Wollenweber and Stapp (1928)) that derived from the Rabenhorst's Fungi europaei #441 (exsiccata) should be treated as the holotype instead of other exsiccata duplicates (isotype) or figure plate (cf., Arts. 9.1 and 9.5 in the Madrid Code).

The species identity of all preserved JCM strains of K. phycomyces was confirmed with ITS and 28S rRNA gene sequences, as listed in the JCM online catalogue. At least, the three examined strains (JCM 18027, JCM 18031, JCM 28336) produced the macroconidial morph on PDA. In JCM 18027, we observed the germination and subsequent growth process of the conidia in the macroconidial and microconidial morphs under the microscope and confirmed that identical colony features were derived from these different conidia, although single-spore isolation was not performed. As a result, we concluded the two different types of conidia were produced by the same fungus. Although Kendrick (1964), Jacobs et al. (2001), and Kiyuna et al. (2012) described the features of their isolates of this species using PDA and 2% malt extract agar, the macroconidial morph was not mentioned at all. We expect that most isolates of K. phycomyces from different continents would produce this previously unnoticed morph in culture. Probably the macroconidial morph has been overlooked until now, because it occurs in the very early stages of growth on PDA plates and is obstructed by the subsequent formation of the conspicuous microconidial morph.

Species of Cylindrocarpon Wollenw. (= Neonectria Wollenw.) and morphologically similar fungi are classified in the Nectriaceae (Hypocreales, Pezizomycotina; Chaverri et al., 2011). In contrast, the exact phylogenetic position of K. phycomyces, which produces somewhat similar macroconidia, is unknown and it is presently treated as Pezizomycotina incertae sedis based on rRNA genes (near the Leotiomycetes; Kiyuna et al., 2012). Because of the lack of gene sequence data beyond that published by Kiyuna et al. (2012), no precise molecular phylogenetic study of K. phycomyces was performed in this paper. Macroconidia produced from monophialides in K. phycomyces mostly have a truncate base, and they are superficially more similar to macroconidia of Cylindrocarpon (with a round base) than Fusarium (with a foot-shaped basal cell). Although these conidia of K. phycomyces are similar to the clavate septate microconidia of Fusarium species (cf., Crous et al., 2021) or the (0-)3-septate cylindrical conidia of Paracylindrocarpon aloicola Crous et al. (Bionectriaceae, Hypocreales, Pezizomycotina; Crous et al., 2016), K. phycomyces is phylogenetically distinct from the Nectriaceae or Bionectriaceae. As far as we know, macroconidial synanamorphs have not been observed in the Pezizomycotina, except the Hypocreales.

Kendrickiella superficially resembles Myxocephala G. Weber, Spaaij & Oberw. (Weber et al., 1989) (Sordariomycetes incertae sedis: Kiyuna et al., 2012; NCBI taxonomy, 2025, see also this database for other higher taxa shown below) more than Phialocephala s. str. (Helotiales: Kiyuna et al., 2012; Tanney and Seifert, 2020), members of the Leptographium complex (Ophiostomatales), and Thysanophora W.B. Kendr. (= Penicillium Link; Eurotiales). Although these genera all belong to Pezizomycotina, they are different from Kendrickiella phylogenetically and taxonomically at the genus, family, order or class levels. We think that the genus Kendrickiella should be treated as at least Pezizomycotina incertae sedis as mentioned by Kiyuna et al. (2012) probably with affinities to the Chaetomellaceae (cf., Fig. 1 in Kiyuna et al. (2012) and NCBI taxonomy (2026)), although different opinions are accepted such as in MycoBank (2025; Ascomycetes), Index Fungorum (2025; Eurotiales), and Fungal Names (2025; Eurotiales). Kendrickiella can be distinguished morphologically from other similar genera by its deep reddish-brown conidiophores, acropleurogenously and verticillately arranged phialides, inconspicuous phialidic collarettes (those features in the microconidial morph), and pleomorphic conidiation (Jacobs et al., 2001; Kendrick, 1964; Kiyuna et al., 2012; Seifert et al., 2011; this paper). Moreover, from physiological and physicochemical viewpoints, the genus is also distinguishable based on resistance to cycloheximide, organic acid production, and abilities of CaCO₃ solubilization (Jacobs et al., 2001; Kiyuna et al., 2012; Sano et al., 2010).

Disclosures

The authors declare no conflicts of interest. This study was conducted in accordance with the current laws in Japan.

Authors' contributions

Conceived and designed the experiments with morphological and cultural studies, writing and editing the draft, and revising the paper: G.O. The final draft read and approved: G.O., M.O.