Hymenochaete angustispora 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 : 171

Hymenochaete angustispora S.H. He & Y.C. Dai , sp. nov. ( Figs. 2a , 3 )

MycoBank: MB 822428

Diagnosis:—The species is distinct by the resupinate basidiocarps, the absence of a hyphal layer, a setal layer thickening with age, with vertically arranged, agglutinated, thick-walled hyphae, and narrowly cylindrical to allantoid basidiospores 5–7 × 1.8–2.2 μm.

Type:— CHINA. Shanxi Province, Yangcheng County, Manghe Nature Reserve, on dead branch of Vitex negundo , 25 August 2016, Dai 17049 (BJFC 023154, holotype).

Etymology:— “ Angustispora ” (Lat.) refers to the narrow basidiospores.

Description:— Basidiocarps annual, resupinate, effused, adnate, not separable from substrate, coriaceous, first as small patches, later confluent up to 8 cm long, 1 cm wide, 80–350 μm thick. Hymenophore surface smooth or locally verruculose, brownish orange (6C4–8), light brown (6D4–8) to dark brown (6F4–8), not cracked or with some scattered crevices; margin indistinct, concolorous with hymenophore surface. Tissues darkening in KOH. Anatomical structure Tomentum and hyphal layer absent; cortex absent or sometimes indistinctly present; setal layer and hymenium present (in sect. Gymnochaete or Paragymnochaete sensu Léger 1998). Hyphal system monomitic. Generative hyphae in basal part hyaline, thin- to thick-walled, simple-septate, interwoven, moderately branched and septate, 1–3.5 μm in diam. Setal layer thickening with age, with several rows of overlapping setae; hyphae in this layer hyaline to yellow, thick-walled, simple-septate, tightly agglutinated, vertically arranged, 4–5 μm in diam. Setae numerous, subulate, yellowish brown to reddish brown, smooth or with a thin hyphal sheath, distinctly thick-walled, with an acute tip, 40–70 × 5–10 μm, embedded or projecting up to 40 μm beyond the hymenium. Cystidia and hyphidia absent. Basidia subclavate to subcylindrical, with walls thickening toward the base, with four sterigmata and a basal simple septum, 16–22 × 4–5 μm; basidioles similar to basidia but smaller. Basidiospores narrowly cylindrical to allantoid, usually tapering toward one end, with an apiculus, hyaline, thin-walled, smooth, IKI–, CB–, usually bearing one to two guttules, (4.5–) 5–7 × 1.8–2.2 μm, L = 5.8 μm, W = 2 μm, Q = 2.7–3.1 (n = 60/2).

Additional specimen examined:— CHINA. Shanxi Province, Yangcheng County, Manghe Nature Reserve, on dead Vitex negundo , 25 August 2016, Dai 17045 (BJFC 023150, paratype).

Remarks:—The narrowly cylindrical to allantoid basidiospores of H. angustispora resemble Hymenochaetopsis ( He & Dai 2012, Yang et al. 2016). However, the blast results and phylogenetic analyses show that H. angustispora is distant from Hymenochaetopsis ( Fig. 1 ). Hymenochaete angustispora is similar to H. fuliginosa (Pers.) Lév. (1846:152) , but this species differs in having darker basidiocarps mostly on gymnosperms, longer setae (65–100 μm in length) and slightly wider basidiospores (1.8–2.6 μm in width, Parmasto 2001). Hymenochaete tenuis Peck (1887:57) distributed in America on gymnosperms is distinguished from H. angustispora by its darker basidiocarps and shorter and wider basidiospores (4.5–5.5 × 2–2.5 μm, Parmasto 2001). Hymenochaete cervinoidea J.C. Léger & Lanq. (1987:43) is similar to H. angustispora by sharing cylindrical to allantoid basidiospores, however, the former species differs in having larger encrusted setae (70–85 × 8–11 μm), and lacking vertically arranged thick-walled hyphae in the setal layer ( Léger 1998). Hymenochaete minuscula G. Cunn. (1957:48) is also similar to H. angustispora , but differs in having smaller setae (40–56 × 5–6 μm) and shorter basidiospores (4–5 × 1.8–2.2 μm, Léger 1998). In the phylogenetic tree ( Fig. 1 ), H. angustispora forms a distinct lineage which is sister to H. ulmicola Corfixen & Parmasto (2005:465) , however, this species can be distinguished by its effuso-reflexed basidiocarps, the presence of a hyphal layer and ellipsoid basidiospores (5.5–7.5 × 3–4 μm, Corfixen & Parmasto 2005).

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 3. Microscopic structures of Hymenochaete angustispora a. Basidiospores. b. Basidia. c. Basidioles. d. Setae. Drawn by Shi- Liang Liu from the holotype.