Boletopsis macrocarpa Y.C. Dai, F. Wu & H.M. Zhou
MycoBank number: 843792
Basidiocarps annual, terrestrial, centrally stipitate, solitary. Pilei circular or irregular, slightly depressed at center, with undulate and sharp margin, up to 18 cm in diam and 3 cm thick at center when fresh. Pileal surface grayish brown (5/6E4) with cream margin (4A2/3) when fresh, becoming blackish blue (20F8) to black upon drying, smooth, azonate. Pore surface white when fresh, becoming clay-buff (6D4) to fawn (7D/E4) upon drying; pores round to angular, some irregular, 1–3 per mm, mature pores bigger than juvenile ones; dissepiment thin, even to slightly lacerate. Context white when fresh, become pale mouse-gray (7C2) when dry, brittle, up to 2.5 cm thick when fresh. Tubes concolorous with pore surface, brittle, up to 5 mm long when fresh. Stipe pale ash-gray (19C2) when fresh, become mouse-gray (9F3) when dry, up to 6 cm long and 4 cm in diam when fresh. Hyphal system monomitic; generative hyphae with clamp connections; gloeoplerous hyphae present, usually 3–11 μm in diam. Pileipellis hyphae hyaline, thin- to thick-walled, 4–9 μm in diam; gloeoplerous hyphae rarely present; tissue darkening in KOH. Contextual hyphae hyaline, thick-walled, rarely branched, interwoven, distinctly inflated, 5–25 μm in diam; gloeoplerous frequently hyphae present, thin-walled, reflective in Melzer’s reagent. Stipitipellis hyphae hyaline, usually thick-walled with a wide lumen, rarely branched, parallel along stipe, straight, uniform, 4–12 μm in diam; gloeoplerous hyphae rarely present. Tramal hyphae hyaline, thin-walled, occasionally branched, interwoven, uniform, 2–4 μm in diam; gloeoplerous hyphae rarely present; cystidia and cystidioles absent; basidia clavate, tetrasterigmatic with a basal clamp connection, 14–19 × 6–7 μm. Basidiospores angular to tubercular with irregular ornaments, hyaline, thin-walled, with a guttule, IKI–, CB–, (4.5–)4.8–6(–6.2) × (3.7–)4–5 μm, L = 5.22 μm, W = 4.31 μm, Q = 1.20–1.22 (n = 90/3).
Additional specimens examined (paratypes): China, Yunnan Province, Chuxiong, Wuding County, on ground in forest of Pinus yunnanensis, alt. 2400 m, 23 September 2021, Dai 23064 (BJFC037635), Dai 23065 (BJFC037636); Dali, Jianchuan County, Laojunshan Nature Reserve, on ground in forest of Pinus yunnanensis, alt. 3100 m, 29 August 2020, Dai 21780 (BJFC035681); Nujiang, Lanping County, Luoguqing Nature Reserve, on ground in forest of Pinus yunnanensis, alt. 3000 m, 3 September 2021, Dai 22748 (BJFC037321); Xinshengqiao National Forest Park, on ground in forest of Pinus yunnanensis, alt. 3000 m, 2 September 2021, Dai 22727 (BJFC037300), Dai 22729 (BJFC037302).
Fig. 1 Phylogeny of species in Boletopsis generated by maximum likelihood based on ITS + nLSU sequence data. Branches are labeled with maximum likelihood bootstrap ≥ 75% and Bayesian posterior probabilities ≥ 0.80, respectively. New species are in bold.