Hymenochaete bambusicola S.H. He

Nie, Ting, Tian, Yan, Liu, Shi-Liang, Yang, Jiao & He, Shuang-Hui, 2017, Species of Hymenochaete (Hymenochaetales, Basidiomycota) on bamboos from East Asia, with descriptions of two new species, MycoKeys 20, pp. 51-65 : 54-55

Hymenochaete bambusicola S.H. He sp. nov. Figs 2, 3

Diagnosis.

This species is distinguished by the presence of dendrohyphidia and skeletal hyphae and the preferred substrate of bamboo tissues.

Holotype.

THAILAND. Chiang Mai Province: Mork Fa, on fallen bamboo, 25 Jul 2016, He 4116 (holotype: BJFC; isotype: MFLU).

Etymology.

" Bambusicola " (Lat.) refers to growing on bamboo.

Fruiting body.

Basidiomes annual, resupinate, effused, closely adnate, coriaceous, at first as small irregular patches, later confluent up to 50 cm long, up to 200 µm thick. Hymenophore smooth, greyish red [7B(3-6)], brownish orange [7C(3-6)], greyish brown (7D3) to light brown [7D(4-6)], not cracked; margin thinning out, light brown [7D(4-8)] to brown [7E(4-8)], usually darker than the hymenophore surface, velvety, up to 1 mm wide. Tissues darkening in KOH.

Microscopic structures.

Hyphal system dimitic. Tomentum absent, cortex and hyphal layer present. Cortex up to 10 µm thick, composed of densely interwoven and agglutinated hyphae, sometimes indistinct. Hyphal layer composed of loosely interwoven skeletal and generative hyphae. Skeletal hyphae dominant, golden yellow to yellowish brown, distinctly thick-walled to subsolid, frequently branched, non-septate, 1-3 µm in diam. Generative hyphae scattered, simple-septate, colorless to pale yellow, thin- to thick-walled, moderately branched, 2-5 µm in diam. Setae scattered to abundant, subulate, yellowish to reddish brown, bearing a thick hyphal sheath and an acute tip, without encrustations or sometime slightly encrusted, originating from the subhymenium or the hyphal layer, (55 –)70–150(– 170) × 7-11 µm, projecting above the hymenium up to 60 µm. Dendrohyphidia numerous, yellowish brown, bearing a thick-walled stem up to 5 µm wide, with branches up to 10 µm long. Basidia clavate to subcylindrical, colorless, with 4 sterigmata and a basal simple septum, 15-18 × 3-4 µm; basidioles similar to basidia but smaller. Basidiospores short cylindrical, slightly curved, colorless, thin-walled, smooth, usually with a small guttula, (4 –)4.5– 6 × 2 –2.5(– 2.8) µm, L = 5.1 µm, W = 2.2 µm, Q = 2.3 (n = 60/2).

Additional specimens examined

(paratypes: BJFC & MFLU). THAILAND. Chiang Mai Province: Mork Fa, on fallen bamboo, 25 Jul 2016, He 4121 & 4131. CHINA. Yunnan Province: Jinghong, Virgin Forest Park, on fallen bamboo, 7 Jun 2011, He 652.

Remarks.

Hymenochaete bambusicola belongs to sect. Hymenochaete sensu Léger (1998) and is morphologically similar to Hymenochaete tropica S.H. He & Y.C. Dai. However, Hymenochaete tropica has a monomitic hyphal system, shorter setae (50-90 × 7-11 µm), and dendrohyphidia with shorter branches ( He and Dai 2012). Hymenochaete innexa and Hymenochaete koeljalgii Parmasto also resemble Hymenochaete bambusicola , but differ from the latter species by having simple hyphidia (not or rarely branched) and absence of skeletal hyphae ( Dai 2010, Parmasto et al. 2014). Hymenochaete ceratophora Job [= Hymenochaete alabastrina G.A. Escobar ex J.C. Léger or Dichochaete ceratophora (Job) Parmasto] is similar to Hymenochaete bambusicola by having a dimitic hyphal system with thick-walled, branched dichohyphae, numerous dendrohyphidia and short cylindrical basidiospores; however, the former species can be distinguished from the latter by having shorter setae (60-110 × 6-10 µm), crystals in hymenium and subhymenium and a distribution in Mesoamerica and South America on unknown substrates ( Léger 1998, Parmasto 2000). Hymenochaete tasmanica Massee ( sect. Hymenochaete ) is somewhat similar to Hymenochaete bambusicola by having dendrohyphidia; however, Hymenochaete tasmanica lacks skeletal hyphae, has a stratified subhymenium and grows on angiosperm substrates ( Léger 1998). In the phylogenetic tree, Hymenochaete bambusicola formed a fully supported clade with Hymenochaete innexa , Hymenochaete koeljalgii and Hymenochaete tropica (Fig. 1).