Phanerochaete fusca Sheng H. Wu, C.C. Chen & C.L. Wei

Wu, Sheng-Hua, Chen, Che-Chih & Wei, Chia-Ling, 2018, Three new species of Phanerochaete (Polyporales, Basidiomycota), MycoKeys 41, pp. 91-106 : 91

Phanerochaete fusca Sheng H. Wu, C.C. Chen & C.L. Wei sp. nov. Figs 3C, 6

Diagnosis.

Phanerochaete fusca is characterised by smooth to tuberculate dark brown hymenial surface, monomitic hyphal system with brown subicular hyphae and leptocystidia with narrow or tapering apices. Additional diagnostic features: hyphae and cystidia usually with adventitious septa, subicular hyphae sometimes swollen at hyphal ends and basidia becoming thick-walled and brownish when old.

Holotype.

CHINA, Hubei Province: Shennongjia Forest Area, Wenshui Forest Farm, 31°44'N, 110°20'E, 1700 m alt., on angiosperm branch, coll. S.H. Wu, 19 Sep 2014, Wu 1409-161 (TNM F0029722).

Etymology.

From fuscus (= dark brown), referring to the colour of the hymenial surface.

Description.

Basidiome resupinate, effuse, adnate, membranaceous, 250-580 μm thick in section. Hymenial surface dark brown, slightly darkening in KOH, smooth to tuberculate, not cracked; margin concolorous, more or less separable, determinate.

Hyphal system monomitic; hyphae simple-septate, clamp connections rarely present in subiculum. Subiculum fairly uniform, with dense texture, 200-480 μm thick; hyphae more or less horizontal, brown, fairly straight, moderately ramified, usually swollen at hyphal ends, usually encrusted near subhymenium, (2.5-) 3-7 (-7.5) μm diam., with slightly thick to up to 2 μm thick walls, with small oily drops, usually with adventitious septa. Hymenial layer thickening, with dense texture, 50-100 μm thick; hyphae more or less vertical, brownish to subcolourless, 2.5-4 μm diam., slightly thick-walled. Leptocystidia numerous, originating from hymenial layer, projecting, cylindrical with narrow or tapering apices, sometimes encrusted, subcolourless to brownish, usually with 1 or 2 adventitious septa, 50-70 × 3.5-5.5 (-6) μm, with thin to up to 1 μm thick walls. Basidia clavate or occasionally narrowly clavate, subcolourless to brownish, sometimes with an adventitious septum, 22-50 × 5-6 μm, with thin to up to 1 μm thick walls, 4-sterigmate. Basidiospores narrowly ellipsoid to subcylindrical, adaxially slightly concave, smooth, thin- to slightly thick-walled, colourless to sometimes brownish, IKI -, CB -, mostly 5.7-7.3 × 3-3.5 μm. [(5.3-) 5.7-7.3 (-7.8) × (2.8-) 3-3.5 (-3.7) μm, L = 6.63 ± 0.64 μm, W = 3.24 ± 0.28 μm, Q = 2.05 (n = 30) (Wu 1409-161)].

Additional specimen examined (paratype).

CHINA. Hubei Province: Shennongjia Forest Area, Wenshui Forest Farm, 31°44'N, 110°20'E, 1700 m alt., on angiosperm branch, coll. S.H. Wu, 19 Sep 2014, Wu 1409-163 (TNM F0029723).

Distribution.

Known from China (Hubei Province).

Remarks.

Phanerochaete stereoides Sheng H. Wu resembles P. fusca in having brown subicular hyphae and leptocystidia. However, hymenial surface of the former is pale greyish-brown, while the latter is dark brown. Moreover, cystidia of P. stereoides are uniformly thin-walled and colourless, not with 1 or 2 adventitious septa. These two species are not closely related according to the phylogenetic analyses (Fig. 2). Phanerochaete porostereoides is the most closely related species (Fig. 2). Like P. fusca , it has brown subicular hyphae, but differs by lacking cystidia and by smaller basidiospores [(4.5-) 4.7-5.3 (-5.5) × (2.3-) 2.5-3.1 (-3.3) μm], according to Liu and He (2016).