Crassisporus microsporus B.K. Cui & Xing Ji

Ji, Xing, Wu, Dong-Mei, Liu, Shun, Si, Jing & Cui, Bao-Kai, 2019, Crassisporus gen. nov. (Polyporaceae, Basidiomycota) evidenced by morphological characters and phylogenetic analyses with descriptions of four new species, MycoKeys 57, pp. 61-84 : 61

Crassisporus microsporus B.K. Cui & Xing Ji sp. nov. Figs 9 , 10

Notes.

Crassisporus microsporus is characterized by pileate basidiocarps, small pores (5-7 per mm), and small, broadly ellipsoid basidiospores (4-5 × 3-3.7 μm).

Holotype.

CHINA. Yunnan Province, Ruili, Mori Tropical Rainforest Park, on living angiosperm tree, 17 September 2017, Cui 16221 (BJFC).

Etymology.

Microsporus (Lat.): referring to the small basidiospores.

Description.

Fruitbody: Basidiocarps annual, pileate, sessile, corky, without odor or taste when fresh, soft leathery to corky upon drying. Pilei semicircular, projecting up to 2 cm, 4 cm wide, and 4.5 mm thick at base. Pileal surface pale yellowish brown to yellowish brown, finely velutinate, concentrically sulcate. Pore surface cream, buff to cinnamon-buff when fresh, buff, pale yellowish brown to yellowish brown when dry; sterile margin distinct, buff, up to 1 mm wide; pores round to angular, 5-7 per mm; dissepiments slightly thick, entire. Context pale yellowish brown to yellowish brown, leathery to corky when dry, up to 1.5 mm thick. Tubes concolorous with context, soft corky to corky, up to 3 mm long.

Hyphal structure: Hyphal system trimitic; generative hyphae bearing clamp connections; skeletal and binding hyphae IKI-, CB-; tissues turning to deep brown in KOH.

Context: Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, 1.2-3.5 μm in diam.; skeletal hyphae dominant, hyaline to pale yellowish brown, thick-walled with a narrow lumen, rarely branched, straight, interwoven, occasionally simple-septate, 2.5-6 μm in diam.; binding hyphae hyaline to pale yellowish brown, thick-walled with a narrow lumen to subsolid, flexuous, frequently branched, interwoven, 0.8-2.5 μm in diam.

Tubes: Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.2-3 μm in diam.; skeletal hyphae dominant, hyaline to pale yellowish brown, thick-walled with a narrow lumen to subsolid, moderately branched, more or less straight, strongly interwoven, 1.5-3 μm in diam.; binding hyphae hyaline to pale yellowish brown, thick-walled with a narrow lumen to subsolid, flexuous, frequently branched, interwoven, 0.8-2.5 μm in diam. Cystidia absent, cystidioles fusoid, hyaline, thin-walled, 12.5-18 × 4-5.5 μm. Basidia clavate, bearing four sterigmata and a basal clamp connection, 14-21 × 4.5-6 μm; basidioles in shape similar to basidia, but distinctly smaller.

Spores: Basidiospores broadly ellipsoid, hyaline, smooth, slightly thick-walled, IKI-, CB-, 4-5(−5.2) × (−2.8)3-3.7(−3.9) μm, L = 4.5 μm, W =3.23 μm, Q = 1.4 (n = 60/1).

Type of rot.

White rot.

Figures

Figure 9. Basidiocarps of Crassisporus microsporus. Scale bars: 1 cm.

Figure 10. Microscopic structures of Crassisporus microsporus (drawn from the holotype) A basidiospores B basidia and basidioles C cystidioles D hyphae from trama E hyphae from context.