Pluteus daqinggouensis T. Bau & M. Liu, 2025

Pluteus daqinggouensis T. Bau & M. Liu , sp. nov. ( Figure. 2 View FIGURE 2 and 3 View FIGURE 3 )

MycoBank number: —856512

Diagnosis: —Characterized by a brownish orange (6C5–6C6) to dark brown (5D3–5D4) pileus with a radial rugose center and a striate margin, pleurocystidia fusiform or subcylindrical, sometimes slightly constricted at the center, and cheilocystidia broadly clavate or ellipsoid.

Etymology: — “ daqinggouensis ” refers to the type locality of this species.

Type: — CHINA, Inner Mongolia Autonomous Region: Tongliao City Daqinggou National Nature Reserve, on decaying wood in broadleaf forests, 42°47′N, 122°10′E, 283 m, 6 Aug. 2017, Tolgor Bau, FJAU 72212 (holotype!).

Description: —Basidiomata small. Pileus 1.2–5 cm in diam, convex to plano-convex when young and applanate when mature, surface greyish orange (6B5–6B6) to brownish orange (6C5–6C6), center brown (5E4) to dark brown (5D3–5D4), with a radial rugose center and a striate margin. Context white (9A1). Lamellae free, ventricose, moderately crowded with 3 series of lamellulae, up to 0.4 cm broad, white (9A1) to pinkish white (9B2), shell pink (8A3). Stipe 2.2–5.0 × 0.2–0.5 cm, cylindrical, pale grey (1B1) to light grey (1C1), surface smooth, slightly silky-shining, solid. Odor and taste not recorded.

Basidiospores 5.3–7.0 × 4.6–6.1μm, Q = 1.02–1.20 (Lm = 5.9 μm, Wm = 5.3 μm, Qm = 1.11), globose, subglobose to broadly ellipsoid, smooth, slightly thick-walled, guttulate, hyaline to pinkish white. Basidia 21–30 × 8–10 μm, clavate, 4-spored, thin-walled, hyaline. Pleurocystidia abundant, 42–73 × 15–35 μm, fusiform or subcylindrical, sometimes with slightly median constriction, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia abundant, 31–64 × 14–34 μm, broadly clavate or ellipsoid, thin-walled, hyaline.Pileipellis a hymeniderm to epithelium, composed of subglobose, spheropedunculate, to obovoid elements, sometimes shortly clavate, 24–75 × 12–50 μm, thin-walled, filled with intracellular pigment light brown, brownish orange pigment. Stipitipellis a cutis, with hyphae 6–12 μm in diameter, cylindrical, hyaline, and thin-walled. Caulocystidia absent. Clamp connections absent in all structures examined.

Habitat: —Growing on decaying wood of broad-leaved forests in summer.

Distribution: —Currently known from Inner Mongolia Autonomous Region and Jilin Province, China.

Additional specimen examined: — CHINA, Inner Mongolia Autonomous Region: Tongliao City Daqinggou National Nature Reserve, 42°47′N, 122°10′E, 283 m, 16 July 2023, Tolgor Bau, Weinan Hou, FJAU72213. CHINA, Jilin Province: Shansongling, 574 m, 43°75′N, 127°33′E, 25 July 2022, Tolgor Bau, Liyang Zhu, FJAU72214.