Cryptomarasmius changchunensis T. Bau & S.Y. Li, sp. nov. (Figure. 2)

MycoBank number: —851386

Diagnosis: —Pileus dark brown to brown; the number of lamellae is less than ten. Basidiospores ellipsoid-fusoid, oblong, subcylindrical; cheilocystidia of type b mostly subfusiform or lageniform, mostly subcapitate (occasionally with slightly thick-walled at the top part), subcylindrical; pleurocystidia, pileocystidia and caulocystidia similar with cheilocystidia of type b, mostly subcapitate.

Etymology: — “changchunensis ” refers to the city where the type specimen was collected.

Type: — CHINA. Jilin Province: Changchun City, campus of Jilin Agricultural University, fallen leaves of deciduous trees, 43°48′N, 125°24′E, 245 m, 17 August 2023, Tolgor Bau and Siying Li (HMJAU 68269, holotype!).

Description: —Pileus less than 4 mm in diameter, hemispherical when young, becoming plano-convex or applanate and slightly depressed at maturity, from dark brown (6F8) at centre to brown (6E6) at margin, with dense granular small bulges, sulcate. Context very thin, whitish (6A1). Lamellae adnexed to adnate, sparsely, whitish (6A1), L=5−6, I=0. Stipe central, 1.0−4.0 cm long, less than 0.1 cm in diameter, filiform, yellowish white (4A2) to brownish orange (6C8) to dark brown (6F8), pruinose, fibrous, hollow. Odor and taste indistinct.

Basidiospores [40/4/2] (5.9)6.1−7.2(7.6)×(2.3)2.4−3.4(3.6) µm, Q=2.10−2.77, Qm=2.43±0.19, ellipsoid-fusoid, oblong, subcylindrical, smooth, thin-walled, hyaline, non-amyloid. Basidia 12−21×4−7 µm, clavate, 4-spored, smooth, thin-walled. Basidioles 11−15×4−5 µm, subfusiform, clavate. Cheilocystidia of two types: a) Rotalis-type broom cells, 9−20×4−16 µm, clavate to broadly clavate, slightly thick-walled, pale yellow (4A3) at the top part. b) subfusiform, narrowly utriform, lageniform, subcapitate (occasionally with slightly thick-wall at the top part), subcylindrical, 18−32×4−9 µm. Pleurocystidia 12−24×5−8 µm, similar with cheilocystidia of type b, lageniform, thin-walled, rarely with a few warts in the middle part. Pileipellis a hymeniderm composed of 10−27×5−18 µm Rotalis-type broom cells, subglobose, clavate, broadly clavate, dark brown (6F8) brownish orange (6C8) or colorless, thick-walled. Pileocystidia 15−20×4−11 µm, lageniform, subcapitate, subcylindrical, rarely with a few warts in the middle part. Stipitipellis a cutis with roughened hyphae, covered with warts or cylindrical excrescences, thick-walled. Caulocystidia abundant, 10−20×3−7 µm, subcylindrical, lageniform, broadly lageniform, subcapitate, subcylindrical. Clamps present in all tissues.

Habitat: —Grow on fallen leaves of deciduous trees in summer.

Known distribution: —Currently known from Jilin Province, China.

Additional specimen examined (paratype): — CHINA. Jilin Province: Changchun City, campus of Jilin Agricultural University, fallen leaves of deciduous trees, 17 August 2023, Tolgor Bau and Xia Wang (HMJAU 68270).