FungiTrechisporalesHydnodontaceaeOrdynetsAlexanderScherfDavidPansegrauFelixDeneckeJonathanLysenkoLudmilaLarssonKarl-HenrikLangerEwaldShort-spored Subulicystidium (Trechisporales, Basidiomycota): high morphological diversity and only partly clear species boundariesMycoKeys2762018201835419910.3897/mycokeys.35.25678 Subulicystidium tedersooi Ordynets, Scherf & Langersp. nov.Figs 4g, h; 10fDiagnosis.

Species with particularly narrow fusiform basidiospores, 8.5–11.5 × 2–2.5 µm and long, 85–125 µm, regularly encrusted cystidia.

Type.

VIETNAM. Ninh Bình Province: Cuc Phuong National Park, sampling area G2906, 20.3500, 105.6026, on fallen decayed twig, 15 Oct 2012, L.Tedersoo (TU 110894).

Etymology.

tedersooi, named after Leho Tedersoo, an Estonian mycologist, the vigorous explorer of the global soil fungal diversity and collector of the type specimen.

Description.

Basidiomata annual, effused, resupinate, soft and fragile, arachnoid, thin, loosely adnate. Hymenophore smooth, finely velutinous due to numerous protruding cystidia, whitish. Margin thinning out, adnate.

system monomitic. All septa with clamps. Subicular and subhymenial layer weakly differentiated, consisting of richly branched hyphae 2–3 µm wide, thin-walled, with rough surface due to a subinvisible hyaline crystal sheath. Cystidia subulate, 85–125 × 4.5–5 µm, usually without basal swelling, terminal, with thick hyaline cell wall and an outer hyaline crystal sheath covering the whole cystidium except the acuminate apex. Crystal protrusions on cystidium are rectangular, moderately large, regularly arranged in longitudinal rows.

Basidia suburniform to cylindrical, 9–13 × 4.5–5, thin-walled, with 4 sterigmata and a basal clamp, occasionally with a thin hyaline crystal collar at the base. Basidiospores narrowly fusiform, L=(7.9–)8.4–11.5(–11.8) µm, W=(1.9–)2.1–2.6(–2.8) µm, Q=(3.4–)3.5–5.0(–5.7), N=81/2, with straight to slightly curved base, thin-walled, often with two large or many smaller oil drops, negative in Melzer’s reagent.

Additional specimens examined.

VIETNAM. Ninh Bình Province: Cuc Phuong National Park, sampling area G2906, 20.3500, 105.6026, on fallen decayed twig, 15 Oct 2012, L.Tedersoo (TU 110895).

Remarks on species.

The narrow spores of S. tedersooi are comparable in width only with S. perlongisporum (see Fig. 10f vs. 10j). However, the spore length of two species drastically differs: 8.4–11.5 µm in S. tedersooi vs. 17–25 µm in S. perlongisporum (Boidin and Gilles 1988). S. tedersooi also has shorter basidiospores and longer cystidia than its sister species S. fusisporum (see Figs 4, 10 and 11 for spore and cystidia comparisons and Figs 12–14 for phylogenetic inference).

Species of Subulicystidium with narrow fusiform basidiospores. Subulicystidium fusisporum (GB:KHL 10360, holotype): a cystidia b crystalline encrustation of hymenium c basidiospores. Subulicystidium inornatum (GB:KHL 10444, holotype): d cystidia e young hymenium with slight overall encrustation f basidiospores. Subulicystidium tedersooi (TU 110894, holotype): g cystidia, h basidiospores. All preparations done in 3% aqueous solution of potassium hydroxide (KOH) mixed with 1% aqueous solution of Phloxine. All scale bars equal 10 µm.

Basidiospore shape and size in all studied species of Subulicystidium. Each species is illustrated by a single specimen and herbarium codes are indicated on the figure.

Basidiospore size range in the short-spored species of Subulicystidium. Only measurements from sequenced or important historical collections were included in calculations (in total 67 specimens, 2840 basidiospores). Boxes (with median inside) delimit the range between 5% and 95% data quantiles, while the whiskers show minimum and maximum values without considering outliers (see Materials and Methods for details on excluding outliers). If more than one sequenced specimen was available for species, raw measurements without outliers were pooled to calculate basidiospore size range of the species. In S. brachysporum, the capital “B” following epithet means morphological species concept following Boidin and Gilles (1988), while “T” means the species as described by Talbot (1958).

Phylogenetic relationship of Subulicystidium based on ITS nrDNA sequences. 50% majority-rule consensus tree from Bayesian analysis is shown, with posterior probabilities above the branches and bootstrap support values from the maximum likelihood estimation below the branches. Tips of the tree are annotated according to morphological identification and marked with colours in non-monophyletic taxa (see legend). In the legend, the capital “B” following epithet in S. brachysporum means morphological species concept following Boidin and Gilles (1988), while “T” means the species as described by Talbot (1958).

Phylogenetic relationship of Subulicystidium based on concatenated ITS+28S nrDNA alignment. 50% majority-rule consensus tree from Bayesian analysis is shown, with posterior probabilities above the branches and bootstrap support values from the maximum likelihood estimation below the branches. Tips of the tree include GenBank/UNITE accession numbers of ITS followed by 28S region. Tips are annotated according to morphological identification and marked with colours in non-monophyletic taxa (see legend). In the legend, the capital “B” following epithet in S. brachysporum means morphological species concept following Boidin and Gilles (1988), while “T” means the species as described by Talbot (1958).

 BoidinJGillesG (1988) Basidiomycètes aphyllophorales de l’Ile de la Réunion. XII: Le genre Subulicystidium Parmasto. Bulletin trimestriel de la Société mycologique de France 104: 191–198. Available from: http://cat.inist.fr/?aModele=afficheN&cpsidt=7053739 [November 10, 2014] TalbotPHB (1958) Studies of some South African resupinate Hymenomycetes. Part II. Bothalia 7: 131–187.