Cotylidia macrosporum Y. Q. Wei & P. M. Wang, sp. nov. (Fig. 2)

MycoBank no.: MB855092

Etymology:—the epithet, macrosporum, referring to the species having relatively larger basidiospores (x = 6.17 ± 0.54 × 4.0 ± 0.47 μm; Q = (1.16–) 1.31–2.0 (–2.37), Q m = 1.57 ± 0.22) than the other Cotylidia species.

Diagnosis:—Basidiome grows on soil. Pileus surface light brownish white at the margin and the centre. Basidiospores (5–) 5.5–7 (–7.2) × 3–4.5 (–5) μm, characterized as an obvious apiculus.

Type:— CHINA. Shandong Province: Ji’nan City, Longdong Scenic Area, on the ground of the forest dominated by Phyllostachys propinqua, elev. 197 m, 26 August 2023, P. M. Wang 345 (EFHAAU10589, holotype!). [GenBank accession numbers—ITS:PP852381, nrLSU: PQ118009; all from holotype].

Description:— Basidiomes pileate, fasciculate, infundibuliform to flabelliform, often in groups becoming confluent, stipitate, 1.8–3.8 cm high, 1.2–4.6 cm wide. Pileus circular, deeply infundibuliform, coriaceous, very thin, pileus surface light brownish white at the margin and the centre (5A1–5A2), sometimes zonate. Stipe central, 0.5–2.0 cm long, 0.2–1.2 cm wide, white (5A1) to light brownish white (5A1–5A2), tomentose, with white mycelial cords at base. Hymenophore thin, coriaceous. Hyphal system monomitic; Generative hyphae without clamps, 5–8 μm wide, hyaline, thin- to thick-walled; hymenial cystidia absent.

Basidiospores [138/14/6] (5–) 5.5–7 (–7.2) × 3–4.5 (–5) μm (x = 6.17 ± 0.54 × 4.0 ± 0.47 μm; Q = (1.16–) 1.31– 2.0 (–2.37), Q m = 1.57 ± 0.22) ellipsoid to oblong, with an obvious apiculus, thin-walled, hyaline, smooth, inamyloid. Basidia narrowly clavate, 35–45 × 5.5–8 μm, 4-spored. Clamp connections absent in all parts of basidiomata.

Habitat and distribution:—fasciculate on the ground in the forest with Pinus massoniana and Castanea mollissima in Puzhao Temple (Tai’an City, Shandong Province, China) and Phyllostachys propinqua in Longdong Scenic Area (Ji’nan City, Shandong Province, China). The sequences on NCBI indicate that this species is also distributed in Guizhou and Sichuan Provinces.

Additional specimens examined:— CHINA. Shandong Province: Tai’an City, Puzhao Temple of Mount Tai Scenic Area, on the ground of the forest dominated by Pinus massoniana and Castanea mollissima, elev. 410m, 12 September 2022, P. M. Wang 083 (EFHAAU10583), 084 (EFHAAU10584), 085 (EFHAAU10585), 086 (EFHAAU10586), 087 (EFHAUU10587) and 088 (EFHAAU10588). Shandong Province: Ji’nan City, Longdong Scenic Area, on the ground of the forest dominated Phyllostachys propinqua, elev. 197m, 26 August 2023, Y. Q. Wei 205 (EFHAAU10590) [GenBank accession numbers—ITS: PQ120976, nrLSU: PQ118037].

Remarks:— Cotylidia macrosporum is characterized by its rugose pileus surface, which appears light brownish white at the margin and the centre and relatively bigger basidiospores measuring (5–) 5.5–7 (–7.2) × 3–4.5 (–5) μm. Phylogenetically, C. macrosporum is related to C. fibrae and C. aurantiaca var. alba in the phylogenetic analyses based on ITS and nrLSU sequence, respectively.