Mycorrhaphium subadustum T. Cao & H.S. Yuan, 2021

Cao, Ting, Yu, Jia-Rui, Nguy ễn, Trang Th ị Thu & Yuan, Hai-Sheng, 2021, Multiple-marker phylogeny and morphological evidence reveal two new species in Steccherinaceae (Polyporales, Basidiomycota) from Asia, MycoKeys 78, pp. 169-186 : 169

Mycorrhaphium subadustum T. Cao & H.S. Yuan sp. nov. Figures 2 , 3

Diagnosis.

Basidiocarps stipitate; pileus semicircular to dimidiate; pileal surface velutinate, concentrically zonate, pileal margin yellowish white; hymenophore hydnoid. Hyphal system dimitic in spine trama and monomitic in context; generative hyphae with clamp connections; cystidia and gloeocystidia absent, cystidiols present. Basidiospores cylindrical to allantoid, CB-, IKI-.

Holotype.

China. Liaoning Province, Huanren County, Laotudingzi Nature Reserve, on fallen branch of angiosperm, 4.VIII.2018, Yuan 12976 (holotype IFP 019374).

Etymology.

Subadustum (Lat.), referring to the affinity with M. adustum .

Description.

Basidiocarps annual, stipitate, solitary or imbricate, corky to soft fibrous, without odor and taste when fresh, light in weight when dry. Pilei semicircular to dimidiate, 2.5-4.5 cm wide and 0.3 cm thick. Pileal surface velutinate, smooth, concentrically zonate, yellowish white to greyish orange (4A2-5B4); margin acute, yellowish white (4A2). Hymenophore hydnoid; spines crowded, evenly distributed, greyish orange (5B4), fibrous, subulate to terete, straight to somewhat flexuous, solitary or confluent, up to 1 mm long, 5-7 per mm; sterile margin smooth, yellowish grey (4B2), up to 2 mm wide. Context yellowish white (3A2), leathery, azonate, homogeneous, up to 0.5 mm thick. Stipe up to 3 cm long, 1 cm wide, straight and base inflated, surface tomentum eventually glabrous, brownish orange (5C4).

Hyphal structure. Hyphal system monomitic in context, dimitic in spine trama; generative hyphae often with clamp connections and simple septate occasionally present; skeletal hyphae thick-walled to subsolid, CB+, IKI-; tissues pale yellow in KOH.

Context. Generative hyphae with clamp connections, colorless, thin- to slightly thick-walled, frequently branched, 3-5 µm diam; skeletal hyphae absent.

Spines. Generative hyphae often with clamp connections, simple-septate occasionally present, colorless, thin- to slightly thick-walled, moderately branched, 2.5-4 µm diam; skeletal hyphae thick-walled to subsolid, unbranched, subparallel along the spine, 3-5 µm diam. Gloeocystidia absent; cystidioles present among the basidia, fusiform, 8-12 × 1.5-3 µm. Basidia clavate, with a basal clamp and four sterigmata, 8-13.5 × 2-3.5 µm; basidioles in shape similar to basidia, but slightly smaller.

Basidiospores cylindrical to ellipsoid, colorless, thin-walled, smooth, CB-, IKI-, (3.5-)3.8-4.0(4.2) × (1.5-)1.8-1.9(-2.0) µm, Lm = 3.89 µm, Wm = 1.83 µm, Q = 2.13-2.17 (n = 60/2).

Type of rot.

White rot.

Distribution.

In temperate zones.

Additional specimen examined.

China. Jilin Province, Antu Country, Changbai Mountain Nature Reserve, Huangsongpu, on fallen branch of angiosperm, 2.VIII.2008, Dai 10173 (IFP 008336).

Figures

Figure 2. Basidiocarps of Mycorrhaphium subadustum (IFP 019374, holotype). Scale bar: 10 mm.

Figure 3. Microscopic structures of Mycorrhaphium subadustum (IFP 019374, holotype) a Basidiospores b Basidia and basidioles c cystidioles d Hyphae from spine trama e Hyphae from context.