Porpomyces submucidus F. Wu & C.L. Zhao, 2015

Porpomyces submucidus F. Wu & C.L. Zhao View in CoL , sp. nov. ( Figs. 4 View FIGURE 4 , 5 View FIGURE 5 )

MycoBank MB 812857

Differs from Porpomyces mucidus Jülich by smaller pores (7–9 per mm) and basidiospores (2.2–2.8 × 1.2–1.8 μm).

Type.— CHINA. Hainan Province, Ledong County, Jianfengling Nature Reserve, on fallen rotten angiosperm wood, 17 June 2014, Y.C. Dai 13708 ( holotype, BJFC 017445).

Etymology.— Submucidus (Lat.) referring to the resemblance with Porpomyces mucidus .

Basidiome. —Annual, resupinate, up to 20 cm long, 5 cm wide, and 0.5 mm thick at the centre, soft when fresh, without odour or taste; becoming soft corky upon drying, sterile margin, cottony to rhizomorphic, thinning out, up to 2 mm. Pore surface white when fresh, becoming cream to buff when dry; pores round to angular, 7 – 9 per mm; dissepiments thin, mostly even. Subiculum white, soft corky, very thin, about 0.1 mm thick. Tubes buff, soft corky, up to 0.4 mm long.

Hyphal structure. —Hyphal system monomitic; generative hyphae smooth, all septa with clamp connections, usually ampullate; hyphae unchanged in KOH.

Subiculum.— Generative hyphae hyaline, thin- to slightly thick-walled, frequently branched with abundant clamp connections, loosely interwoven, IKI–, CB–, 2.5–4 μm in diam.

Tubes. —Tramal hyphae hyaline, thin-walled, frequently branched with abundant clamp connections, loosely interwoven, IKI–, CB–, 2–3 μm in diam. Cystidia and cystidioles absent; basidia barrel-shaped, thin-walled with a basal clamp and four sterigmata, 6–7 × 4–5 μm; basidioles in shape similar to basidia, slightly smaller.

Spores. —Basidiospores ellipsoid, hyaline, thin-walled, smooth, tapering towards the apiculus, IKI–, CB–, (2–)2.2–2.8(–3) × 1.2–1.8(–2) μm, L = 2.36 μm, W = 1.53 μm, Q = 1.54 (n=30/1).

Additional specimens examined.— Porpomyces submucidus . CHINA. Hainan Province, Ledong County, Jianfengling Nature Reserve, on fallen rotten angiosperm wood, 17 November 2007, B.K. Cui 5183 (BJFC 003224). Porpomyces mucidus . CHINA. Shanxi Province, Jiaocheng County, Pangquangou Nature Reserve, on fallen trunk of Picea , 12 October 2004, Yuan 860 (BJFC 000401). ITALY. Rome, Castal Fusano, on rotten wood of Pinus , 26 April 2005, Dai 6549 (BJFC 000403). FINLAND. Etelä-Häme, Lammi Biological Station, on fallen trunk of Betula , 8 October 1992, Dai 222 (BJFC 000402). Rigidoporus minutus . CHINA. Hainan Province, Baoting County, Diaoluoshan Nature Reserve, on rotten angiosperm, 14 June 2014, Dai 13602A (BJFC017341), Dai 13605A (BJFC017344).

Remarks. — Porpomyces submucidus is rather similar to P. mucidus , but the latter has larger pores as 4–5 per mm, fusoid cystidioles, presence of large crystals among hyphae and hymenia, and larger basidiospores measuring (2.7–) 2.8–3.9(–4.4) × (1.9–)2–2.8(–3) μm, L = 3.2 μm, W = 2.3 μm, Q = 1.3–1.4 ( Niemelä 2005). In addition, Porpomyces mucidus has a wide distribution in temperate areas in north hemisphere ( Gilbertson & Ryvarden 1986, Núñez & Ryvarden 2001, Dai 2012, Ryvarden & Melo 2014), while Porpomyces submucidus is found in tropical forest in Southern China so far.