Subulicystidium grandisporum Ordynets & K.H.Larss., 2018

Ordynets, Alexander, Scherf, David, Pansegrau, Felix, Denecke, Jonathan, Lysenko, Ludmila, Larsson, Karl-Henrik & Langer, Ewald, 2018, Short-spored Subulicystidium (Trechisporales, Basidiomycota): high morphological diversity and only partly clear species boundaries, MycoKeys 35, pp. 41-99 : 41

Subulicystidium grandisporum Ordynets & K.H.Larss. sp. nov. Figs 6a-c ; 10i

Diagnosis.

Species with the largest cylindrical basidiospores ever observed in the genus (10.5-14.5 × 3.3-3.9 µm) and relatively large cystidia with prominent regular encrustation.

Type.

COSTA RICA. Cartago: Faldas del volcano Irazu , 1800 m, on decayed twig, 28 May 1991, L.Ryvarden (LR 29162 in O:F 506781) .

Etymology.

grandisporum (Lat.), having large basidiospores.

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, pruinose, adnate.

system monomitic. All septa with clamps. Subiculum thin, with loosely interwoven richly branched hyphae 3-4 µm wide, thin-walled, hyaline and smooth. Subhymenium thin, compact, with richly branched hyphae 3-3.5 µm wide, often covered with thin hyaline crystalline sheath. Cystidia subulate, 70-90 × 5-7 µm including encrustation, projecting up to 60 µm, without basal swelling, terminal or pleural, with thick hyaline cell wall and outer hyaline crystalline sheath covering the whole cystidium except the thin-walled, tapering apex. Crystal protrusions on cystidium are large, clearly rectangular to rounded, rather sparsely arranged in longitudinal rows.

Basidia suburniform, 13-19 × 5.5-7 µm, thin-walled, with 4 sterigmata and a basal clamp, often with hyaline crystalline collar at the base. Basidiospores cylindric, adaxial side slightly concave, L=(10-)10.6-14.5(-15.3) µm, W=(3.2-)3.3-3.9(-4.2) µm, Q= (2.9-)3.0-4.0, N=48/1, with minute apiculus, smooth, thin-walled, hyaline, negative in Melzer’s reagent.

Remarks on species. Until now, it is the only known Subulicystidium species with such large cylindrical basidiospores. Additionally, large cystidia with regular large protrusions, together with large basidia, make the species remarkable.

Figures

Figure 6. Species of Subulicystidium with long cylindric basidiospores. Subulicystidium grandisporum (LR 29162 in O: F 506781): a hymenium with rich crystalline encrustation b cystidia c basidiospores. Subulicystidium obtusisporum (FR: W 213 - 3 - I): d cystidia e basidiospores. Subulicystidium rarocrystallinum (LR 15483 in O: F 918488, holotype): f cystidia g hymenium 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.

Figure 10. 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.