Lyomyces granulosus Yurchenko & Langer, 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 granulosus Yurchenko & Langer sp. nov.

Figs 3 C, D , 5 , 16 C

Type.

Costa Rica • Alajuela Province: near Fraijanes and Poás volcano , 1940 m a. s. l., secondary evergreen tropical forest in a ravine, on wood and bark of dead branch or stem 30 mm in diam., 11 Feb 1989, E. Langer, G. Wagner No. 223 (holotype: KAS-GEL 1662 ; isotype: CFMR). GenBank: ITS = PP 471799 .

Etymology.

granulosus (Lat.) = having a grainy structure, due to the morphology of basidioma.

Description.

Basidiomata effused, 0.1–3 cm in extent, grandinioid-farinaceous to membranaceous, soft and fragile, usually consisting of as-if-confluent grains, 50–115 μm thick. Hymenial surface colliculose, whitish or creamish. Margin concolourous, pruinose, diffuse, 0.3–1 mm wide. Hyphal system monomitic, hyphae clamped at all septa, thin-walled, colourless. Subiculum thin, little differentiated from subhymenium. Subicular hyphae moderately branched, comparatively short-celled, 1.8–3.5 (– 4) μm wide, smooth; subhymenial hyphae richly branched, 2–3.2 μm wide, smooth or scarcely encrusted. Cystidia of several types: 1) capitate and subcapitate common, 15–47 × 4–5.5 μm, often with several slight constrictions, smooth to richly encrusted in the lower 2 / 3 of their length; 2) fusoid and subcylindrical scattered, 30–55 × 3–4.5 (– 6) μm, smooth to richly encrusted. Basidioles mostly clavate, 7.5–20 × 3.5–5 (– 6) μm, smooth. Basidia 14–19 × 4.5–4.7 μm, smooth, with four sterigmata 2–3 × 0.5–0.7 μm. Basidiospores broadly ellipsoid, (4.5 –) 5–5.5 (– 6.3) × (3.3 –) 3.5–4 μm (in holotype L = 5.1 μm, W = 3.7 μm), Q = 1.2–1.4 (– 1.6), thin- to often slightly thick-walled, smooth, colourless, Mz –, acyanophilous to slightly cyanophilous; apiculus small, but distinct.

Distribution.

So far, known from Costa Rica and Panama.

Ecology.

The species grows on dead decorticated small-sized wood in evergreen tropical forests, with a supposed preference for mountain ravines.

Additional specimens examined

(paratypes). Costa Rica • The same locality as holotype, on wood and bark of dead stem 7–15 mm in diam., 11 Feb 1989, E. Langer, G. Wagner ( KAS-GEL 1650 ) ; Panama • Chiriquí Province: W of Boquete town, Bajo Boquete community , 08 ° 46.58 ' N, 082 ° 28.17 ' W, 1450 m a. s. l., evergreen montane tropical forest, bottom of canyon with a rivulet, on a decorticated fallen branch, 27 Jul 2019, E. Yurchenko EYu 190727-8 b ( BLS M-2975 ; GenBank: ITS = PP 471798, 28 S = PP 471819) .

Notes.

The main diagnostic features of this species are the granulose structure of basidioma, thin-walled hyphae, presence of slightly constricted capitate cystidia, and broadly ellipsoid basidiospores with thin or slightly thickened walls. The species is morphologically close to L. sambuci , L. denudatus , and L. fimbriatus . In contrast to the new species, L. sambuci has less encrusted capitate cystidia and spores often with a drop inside. Lyomyces fimbriatus and L. denudatus have larger, thin-walled spores. Moreover, L. fimbriatus has an odontoid hymenial surface.

Figures

Figure 3. Macromorphology of Lyomyces species A, B L. boquetensis, holotype (BLS M- 5238) C L. granulosus, holotype (KAS-GEL 1662) D L. granulosus, BLS M- 2975 E, F L. napoensis, holotype (BLS M- 2610) G, H L. neocrustosus, holotype (BLS M- 5239). Scale bars: 1 mm.

Figure 5. Micromorphology of Lyomyces granulosus (holotype, KAS-GEL 1662) A – D vertical sections through basidiomata E subicular hyphae F cystidia in KOH G cystidia in Mz H basidioles I basidia J basidiospores in KOH K basidiospores in Mz. Scale bars: 100 μm (A, B); 20 μm (C); 10 μm (D – I); 5 μm (J, 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.