Hymenochaete verruculosa S.H. He & Y.C. Dai, 2017

He, Shuang-Hui, Liu, Shi-Liang, Li, Hai-Jiao & Dai, Yu-Cheng, 2017, Two new species of Hymenochaete (Hymenochaetaceae, Basidiomycota) and H. colliculosa new to China from Shanxi Province, Phytotaxa 324 (2), pp. 168-178 : 173-174

Hymenochaete verruculosa S.H. He & Y.C. Dai , sp. nov. ( Figs. 2b , 4 )

MycoBank: MB 822427

Diagnosis:—The species is distinct by its effuso-reflexed basidiocarps, verruculose hymenophore surface, the presence of tomentum, the cortex and hyphal layer, and small ellipsoid basidiospores 3.5–4.5 × 2–2.8 μm.

Type:— CHINA. Shanxi Province, Yangcheng County, Manghe Nature Reserve, on rotten Cornus stump, 25 August 2016, Dai 17047 (BJFC 023152, holotype).

Etymology:— “ Verruculosa ” (Lat.) refers to the verruculose hymenophore surface.

Description:— Basidiocarps annual, resupinate to effuso-reflexed, adnate, easily detached from substrate, coriaceous to soft corky; effused part up to 7 cm long, 3 cm wide; reflexed part projecting up to 0.5 cm, up to 0.6 mm thick. Abhymenial surface grey (6D1–F1), brownish grey (6D2–F2) to greyish brown (6D3–F3), glabrous, sulcate; margin sharp, lighter than abhymenial surface. Hymenophore surface verruculose, with numerous small tubercles, brown (6E4–8) to dark brown (6F4–8), not cracked; margin thinning, distinct, brownish orange (6C3–8) to light brown (6D4–8), up to 0.2 cm wide. Tissues darkening in KOH. Anatomical structure: Tomentum, cortex, hyphal layer, setal layer and hymenium present (in sect. Hymenochaete sensu Léger 1998 ). Cortex distinct as a dark line up to 50 μm wide between tomentum and hyphal layer, composed of densely agglutinated hyphae. Hyphal layer yellowish brown; hyphal system monomitic; generative hyphae in this layer hyaline to golden brown, thin- to thick-walled, simple-septate, rarely branched, moderately septate, interwoven, more or less regularly arranged, 1–2.5 μm in diam. Setal hyphae present, scattered, reddish brown, sinuous, usually bent toward setal layer, distinctly thick-walled with a narrow lumen, with an acute tip, up to 100 × 5 μm. Setal layer thickening with age, with one to several overlapping setae; generative hyphae in this layer hyaline to golden brown, thin- to thick-walled, frequently branched and septate, interwoven, agglutinated, 1.5–3 μm in diam. Setae numerous, subulate, reddish brown to dark brown, smooth, distinctly thick-walled with a narrow lumen, with an acute tip, 40–70 (–85) × 5–7 μm, embedded or projecting up to 35 μm beyond the hymenium. Cystidia and dendrohyphidia absent. Simple hyphidia present, scattered, yellowish brown, thick-walled. Basidia subclavate to subcylindrical, usually with walls thickening toward the base, sinuous, with four sterigmata and a basal simple septum, 16–20 × 3–3.8 μm; basidioles similar to basidia but slightly smaller. Basidiospores ellipsoid, with an apiculus, hyaline, thin-walled, smooth, IKI–, CB–, usually bearing a guttule, 3.5–4.5 (–5) × 2–2.8 μm, L = 4 μm, W = 2.3 μm, Q = 1.7–1.8 (n = 60/2).

Additional specimen examined:— CHINA. Shanxi Province, Yangcheng County, Manghe Nature Reserve, on rotten Cornus stump, 25 August 2016, Dai 17052 (BJFC 023157, paratype).

Remarks:— Hymenochaete verruculosa is similar to H. rubiginosa (Dicks.) Lév. (1846:151) , but the latter species differs in having smooth to sparsely tuberculate and harder basidiocarps, wider setae (8–10 μm in width), and slightly longer basidiospores (3.8–5.5 μm in length), and grows mainly on Quercus and Castanea ( Parmasto 2001) . Hymenochaete colliculosa resembles H. verruculosa by sharing the densely tuberculate hymenophore, but differs in having larger setae (80–110 × 7.5–11 μm) and larger ellipsoid basidiospores (5.5–7.5 × 3.6–4.8 μm, Parmasto 2005). Hymenochaete tuberculosa Cooke (1881:101) has tubercles in the hymenophore, but it differs from H. verruculosa in having resupinate, cracked, thick, and hard basidiocarps ( Léger 1998, Parmasto 2005). Hymenochaete semistupposa Petch (1925:278) is also similar to H. verruculosa ; however, it has resupinate smooth basidiocarps and is found in tropical areas on Myrtaceae ( Parmasto & Gilbertson 2005) . In the phylogenetic tree ( Fig. 1 ), H. verruculosa forms a distinct lineage.

Figures

FIGURE 1. Phylogenetic tree inferred from maximum likelihood (ML) analysis based on a concatenated dataset of ITS and 28S sequences data of Hymenochaete species. Branches are labelled with maximum likelihood bootstraps and maximum parsimony bootstraps ≥ 50%, and Bayesian posterior probabilities ≥ 0.95.

FIGURE 2. Basidiocarps of Hymenochaete species a. Hymenochaete angustispora (Dai 17049, holotype). b. Hymenochaete verruculosa (Dai 17047, holotype). c–d. Hymenochaete colliculosa (Dai 16427). Bars = 1 cm. Photos by Shuang-Hui He.

FIGURE 4. Microscopic structures of Hymenochaete verruculosa a. Basidiospores. b. Basidia. c. Basidioles. d. Hyphidia. e. Setae. f. Hyphae from hyphal layer. Drawn by Shi-Liang Liu from the holotype.