Lyomyces subcylindricus Yurchenko & Riebesehl, 2024

Yurchenko, Eugene, Langer, Ewald & Riebesehl, Janett, 2024, A high species diversity of Lyomyces (Basidiomycota, Hymenochaetales) in Central and South America, revealed after morphological and molecular analysis, MycoKeys 109, pp. 131-169 : 131-169

Lyomyces subcylindricus Yurchenko & Riebesehl sp. nov.

Figs 8 H , 15 , 16 H

Type.

Panama • Chiriquí Province: W of Boquete town, Bajo Boquete community , 08 ° 46.45 ' N, 082 ° 28.03 ' W, about 1400 m a. s. l., evergreen montane tropical angiosperm forest, on decorticated fallen branch, 27 Jul 2019, E. Yurchenko EYu 190727-25 (holotype: BLS M-2668 ; isotype: CFMR). GenBank: ITS = PP 471817 .

Etymology.

The epithet refers to the subcylindrical shape of cystidia and basidiospores.

Description.

Basidiomata effused, 0.15–1.5 cm in extent, soft- to moderately membranaceous, 30–85 μm thick between aculei. Hymenial surface minutely odontoid or warted, dirty white with faint cream tinge; aculei or warts conical to cylindrical, 6–8 / mm, 30–55 μm high, 20–50 μm in diam. Margin slightly paler than the main surface, mould-like, 0.3–1 mm wide. Hyphal system monomitic, hyphae clamped at all septa, moderately branched, colourless, with scattered to abundant loosely attached rosette-shaped crystals. Subicular hyphae (1.7 –) 2–4 μm wide, thin- to slightly thick-walled; subhymenial hyphae 1.7–4.3 μm wide, thin-walled, somewhat short-celled and inflated. Cystidia smooth or variously encrusted, of several types: 1) subulate (fusoid) scattered to common, (18 –) 20–33 × 2.5–4.3 μm; 2) subcylindrical and cylindrical scarce, 18–32 × 2.5–4.5 μm; 3) subcapitate or capitulate rare, 12–20 × 2–3 μm. Outgrowths of hymenial surface consisting in the upper part of subulate and subcylindrical cystidia. Basidioles ovoid, short cylindrical, subclavate, 7.5–13.5 × 3.5–4.5 μm. Basidia utriform to narrowly utriform, 15–20 × 3.5–4.5 μm; sterigmata four, 2–3 × 0.7–1 μm. Basidiospores narrowly ellipsoid to subcylindrical, with adaxial side from slightly convex to slightly concave, (4.5 –) 5–6 (– 6.5) × 2.5–3.3 (– 3.5) μm (in holotype L = 5.5 μm, W = 2.95 μm), Q = 1.6–1.8 (– 2), thin-walled, smooth, colourless, Mz –, acyanophilous; apiculus minute.

Distribution.

So far, known from the western part of Panama.

Ecology.

The fungus grows on dead wood in evergreen montane tropical angiosperm forests.

Additional specimen examined

(paratype). Panama • Chiriquí Province: W of Boquete town, Bajo Boquete community , 08 ° 46.58 ' N, 082 ° 28.17 ' W, about 1450 m a. s. l., evergreen montane tropical angiosperm forest, bottom of canyon with a rivulet, on a fallen partly corticated woody stem, 27 Jul 2019, E. Yurchenko EYu 190727-10 a ( BLS M-2992 ). GenBank: ITS = PP 471816; 28 S = PP 471832 .

Notes.

The main diagnostic features of this species are minutely odontoid, dirty white basidiomata, thin-walled hyphae, the presence of subulate and subcylindrical cystidia, and subcylindrical, thin-walled basidiospores. The species is morphologically closest to L. crustosus . It differs from the latter by its whitish, densely and minutely odontoid hymenial surface, looser texture of basidioma, not copious subulate cystidia, and the presence of subcylindrical cystidia.

Figures

Figure 8. Macromorphology of Lyomyces species A L. oleifer, holotype (KAS-Ec 47-2001) B L. orarius, holotype (BLS M- 2995) C L. pantropicus, holotype (BLS M- 2679) D L. pantropicus, BLS M- 3545 E L. parvus, holotype (KAS-GEL 1599) F L. parvus, BLS M- 2990 G L. sceptrifer, holotype (KAS-Ec 661-2002) H L. subcylindricus, holotype (BLS M- 2668). Scale bars: 1 mm.

Figure 15. Micromorphology of Lyomyces subcylindricus (holotype, BLS M- 2668) A, B vertical sections through basidioma C subicular hyphae D portions of subhymenium and hymenium E Subulate cystidia F capitulate, subcylindrical, and cylindrical cystidia G basidioles H basidia I basidiospores. BLS M- 2992: J basidia K basidiospores. Scale bars: 100 μm (A); 20 μm (B); 10 μm (C – H, J); 5 μm (I, K).

Figure 16. SEM of crystalline deposits on hymenial elements and hyphae in holotypes of Lyomyces species A, B L. boquetensis C L. granulosus D L. napoensis E L. neocrustosus F L. pantropicus G L. parvus H L. subcylindricus. Scale bars: 5 μm.