Panaeolus grandis M. Q. He & R. L. Zhao, sp. nov.

Panaeolus grandis M. Q. He & R. L. Zhao sp. nov. Fig. 7 Etymology. grandis (Lat.) refers to the relatively large basidiomes of this species in Panaeolus. Diagnosis. Panaeolus grandis has relatively large basidiome with a campanulate, brown pileus and long stipe; cheilocystidia tibiiform with an inflated base. Holotype. CHINA. Xizang Autonomous Region: Shigatse Municipality, Yadong County, 27.25.17°N, 88.56.32°E, alt. 3024 m, 26 July 2022, Mao-Qiang He, HMAS 287495 (ZRL 20220208). Description. Pileus 13.9–75.6 mm in diam., campanulate, disc light brown (pantone 3596 c), brown (pantone 2441 c), paler elsewhere (pantone 4755 c), surface dry, hygrophanous, sometimes rugulose around disc, margin straight, sometimes slightly uplifted. Lamellae adnate, subdistant, broad, mottled grayish to blackish, entire, edge white. Stipe equal, hollow, 63.8–156.8 mm long, 1.7–5.0 mm thick, light brown, the same color as pileus (pantone 4755 c), smooth, longitudinally striate, pruinose, base with whitish mycelium. Basidiospores 12.0–13.9 × 7.1–9.6 μm, [x = 12.9 ± 0.6 × 8.1 ± 0.6, Q = 1.3–1.8, Q m = 1.6 ± 0.1, n = 20], ellipsoid, broadly ellipsoid, smooth, blackish brown, thick wall with germ pore. Basidia 22.3–29.8 × 8.9–10.6 μm, 4 - spored, smooth, hyaline. Cheilocystidia 25.7–41.9 × 5.3–9.3 μm, tibiiform with an inflated base, hyaline, smooth. Pleurocystidia absent. Cuticle composed of large vesicles, pileocystidia not observed. Caulocystidia 43.9–102.2 × 6.0–10.5 μm, cylindrical, hyaline, some with brown pigment inside. Habitat. Grows on soil in grasslands, pine forests. Psilocybin-producing. Nonproducing (ZRL 20220208, see Suppl. material 1: fig. S 14). Notes. According to the results of the phylogenetic analyses, P. grandis is clustered in subclade A 1. Morphologically, P. grandis differs from other species in Panaeolus by its relatively large-sized basidiome with a campanulate, brown pileus and a long stipe. Although P. pallidus also has a basidiome of similar size, it forms larger basidiospores (17.2 ± 0.6 × 11.8 ± 0.4 μm) compared with P. grandis. Specimen examined. China. Xizang Autonomous Region: Shigatse Municipality, Yadong County, 27.25.20°N, 88.55.6°E, alt. 3254 m, 27 July 2022, Mao-Qiang He, ZRL 20220352.