Hymenochaete micropora L.W. Zhou & Y.C. Dai.
Index Fungorum number: IF551490; Facesoffungi number: FoF01004
Basidiocarps annual, pileate, sometimes attached by a lateral tapering base, imbricate, corky and without odour or taste when fresh, hard corky and brittle when dry. Pilei dimidiate to usually fan-shaped, projecting up to 3 cm, 4 cm wide and 2 mm thick at base. Pileal surface yellowish brown to reddish brown, narrowly concentrically zoned in different shades, tomentose to velutinate; margin acute, convex when dry. Pore surface rust-brown to greyish brown; sterile margin distinct, yellowish brown, up to 1 mm wide; pores circular to angular, 9–11 per mm; dissepiments thin, entire. Context reddish brown, up to 1 mm thick, duplex, towards the to mentum separated by one black line, lower part hard corky, upper tomentum soft corky. Tubes honey-yellow, paler than pores, up to 1 mm long. Hyphal system monomitic; generative hyphae with simple septa; tissue darkening and slightly swelling in KOH. Contextual hyphae in the lower dense context yellowish, thick-walled with a wide lumen, unbranched, interwoven, 2.5–4μm in diam; hyphae in the black line dark brown, distinctly thick-walled with a narrow lumen, strongly agglutinated; hyphae in the upper tomentum yellow to brown, thick-walled with a wide to narrow lumen, unbranched, regularly arranged, 3–4.5μm diam. Tramal hyphae varying from pale yellowish and slightly thick-walled to brown and thick-walled with a wide lumen, occasionally branched close to a septum, frequently simple septate, straight, parallel along the tubes, 2–3.5 μm diam. Setae frequent, distinctly subulate, arising from trama, most part embedded in hymenium, slightly curved at base, dark brown, thick-walled, 10–28×4–8μm; cystidia and cystidioles absent; basidia more or less barrel-shaped, with four sterigmata and a simple septum at the base, 7–12×4–6 μm; basidioles in shape similar to basidia, distinctly smaller. Basidiospores ellipsoid, hyaline, thin-walled, smooth, IKI –, CB –, (2.5 – )2.6 – 3(−3.1) × (1.5–)1.6–2(−2.1) μm, L=2.81 μm, W=1.8 μm, Q=1.56 (n=30/1). (Fig.1)
Material examined: CHINA, Yunnan Province, Tengchong County, Gaoligong Mountain, on fallen angiosperm trunk, 24 October 2009, Cui 8057 (BJFC006546, holotype; IFP019137, isotype).
Notes: Hymenochaete micropora has similar basidiospores to H. porioides T. Wagner & M. Fisch. (2.5–3.5×1.5–2 μm; 2.5–3.1×1.5–1.9 μm, measured from LWZ 20140719–11). However, the small pores make H. micropora distinguished from all other known species of Hymenochaete. In addition, the duplex context of H. micropora is separated by one black line, while H. porioides has two black lines in context. In ITS-based phylogeny, the clade formed by two H. micropora was also distinct from that of H. porioides.
Fig. 1 Phylogenetic position of Hymenochaete micropora (in bold-face) inferred from ITS sequences. Topology is from maximum likelihood analysis; statistical values from maximum likelihood and maximum parsimony (simultaneously above 50 %) for each node are indicated at the branches.