Pluteus liaoheensis T. Bau & M. Liu, 2025

Pluteus liaoheensis T. Bau & M. Liu , sp. nov. ( Figure. 4 View FIGURE 4 and 5 View FIGURE 5 )

MycoBank number: —856514

Diagnosis: — Pluteus liaoheensis can be easily distinguished from its closely related species by brown (5F6) to dark brown (8F5–8F6) pileus, with granular dark brown (6F7–6F8) hairs. Pleurocystidia are rare, typically clavate when present. Pileipellis trichoderm to intricate trichoderm, composed of clavate, cylindrical, fusiform elements, which tightly clustered.

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

Type: — CHINA, Inner Mongolia Autonomous Region: Tongliao City Liaohe Park, on soil, 43°64′N, 122°26′E, 178.8 m, 5 Sep. 2023, Tolgor Bau, Hong Cheng, FJAU 72215 (holotype!).

Description: —Basidiomata small. Pileus 0.7–1.2 cm in diam, convex to plano-convex, surface brown (5F6) to dark brown (8F5–8F6), with radial dark brown (6F7–6F8) hairs. Context thin, white (9A1). Lamellae free, ventricose, moderately crowded with 2–3 series of lamellulae, up to 0.2 cm broad, pinkish white (9A2) to shell pink (8A3). Stipe 1.0–2.3 × 0.1–0.2 cm, cylindrical, surface smooth, light grey (1C1), grey (2B1) to olive grey (2B2), with fibrillosestriate lengthwise, hollow, sometimes with white (1A1) mycelium at the base. Odor and taste not recorded.

Basidiospores 5.6–6.8 × 5.2–6.2 µm, Q = 1.06–1.21 (Lm = 6.2 μm, Wm = 5.5 μm, Qm = 1.12), subglobose to broadly ellipsoid, smooth, slightly thick-walled, guttulate, hyaline to pinkish white. Basidia 19–26 × 7–10 µm, clavate to cylindrical, 4 (2) -spored, thin-walled, hyaline. Pleurocystidia rare or absent, 32–52 × 16–19 µm, clavate or obovoid, thin-walled, hyaline. Lamella edge sterile with crowded cheilocystidia. Cheilocystidia abundant, 25–80 × 12–25 µm, narrowly clavate or clavate, thin-walled, hyaline. Pileipellis trichoderm to intricate trichoderm, composed of clavate, cylindrical, fusiform elements, arranged in dense clusters, 28–91 × 9–32 µm, thin-walled, brown, reddish brown, hyaline. Stipitipellis a cutis, with hyphae 4–10 μm in diameter, cylindrical, hyaline, thin-walled. Caulocystidia absent. Clamp connections absent in all structures examined.

Habitat: —Growing on soil in summer.

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

Additional specimen examined: — CHINA, Inner Mongolia Autonomous Region: Tongliao City Liaohe Park, on soil, 43°64′N, 122°26′E, 178.8 m, 5 Sep. 2023, Tolgor Bau, Hong Cheng, FJAU72216. CHINA, Inner Mongolia Autonomous Region: Hinggan League, Tuquan county, on soil, 45°22′N, 121°35′E, 307.9 m, 26 Aug. 2023, Tolgor Bau, Weinan Hou, FJAU72430.