Psathyrella senex ( Peck 1888: 70 ) A.H. Sm. (1972: 230)

Yan, Jun-Qing & Bau, Tolgor, 2017, New and newly recorded species of Psathyrella (Psathyrellaceae, Agaricales) from northeast China, Phytotaxa 321 (1), pp. 139-150 : 144

Psathyrella senex ( Peck 1888: 70) A.H. Sm. (1972: 230) Figs. 1d , 5 .

Description:— Pileus 10–30 mm, in early stage hemispherical, brown (6D7–6E8), orange (6A6–6B7) towards margin, distinctly striate, at maturity conical, occasionally obtuse, hygrophanous, striate up to 3/4 from margin, brown (6D6– 6D7), when drying becoming fawn (6C4–6D5); veil with a thin coating of fibrils, evanescent. Context dirty white (6A1) to fawn (6C4–6D5), very thin and fragile. Lamellae 1.5–3.0 mm broad, close, thin, adnate, grayish brown to brown (6D3–6D5), edges even. Stipe 25–55mm long, 2.0–3.0 mm thick, upper 1/2 white (6A1), lower down grayish brown to pale brown (6C4–6C5), cylindrical, hollow, equal, fragile, surface covered with white (6A1) fibrils, evanescent. Odour and taste indistinctive. Spore print not recorded.

Spores 6.8–8.3(8.8) × 4.1–5.0 μm, Q=1.4–1.9, ellipsoid to elongated-ellipsoid, pale brown to brown in 5% KOH, inamyloid, smooth, with or without a guttule, germ pore indistinct. Basidia 19–26 × 7.3–9.8 μm, 4-spored, clavate. Pleurocystidia 49–66 × 11–16 μm, fusoid with obtuse apex, occasionally branching at apex, thin, smooth or with granules adhering around the apex, colorless in 5% KOH. Cheilocystidia resembling the pleurocystidia, 29–39 × 9.8– 12.2 μm, clavate and spheropedunculate hyphae present, 34–39 × 15–17 μm. Caulocystidia absent. Trama of gills with irregularly shaped hyphae, hyaline. Pileipellis a 1–2 deep layer of vesiculose hyphae, 12–34 μm in diameter. Clamps present.

Habit and habitat:—Scattered on decaying wood.

Known distribution:— Canada ( Smith 1972), China, Czechia ( Vašutová 2006), Germany ( Örstadius et al. 2015), United States of America ( Smith 1972).

Material examined:— CHINA, Jilin Province: Changbai Mountain, Erdaobaihe Town , Yanbian KoreanAutonomous Prefecture , 15 June 2016, Jun-Qing Yan HMJAU37306, HMJAU37307, HMJAU37308, HMJAU37309 ; 17 June 2016, Jun-Qing Yan HMJAU37310; 17 October 2012, Tolgor Bau HMJAU25334 ( HMJAU!) .

Figures

FIGURE 1. a) Psathyrella subspadiceogrisea (HMJAU35992) b) Psathyrella boreifasciculata (HMJAU27556) c) Psathyrella gordonii (HMJAU35983) d) Psathyrella senex (HMJAU37306). Bars: a–d=10 mm. Photos a, b, d by Jun-Qing Yan; Photo c by Tolgor Bau.

FIGURE 5. Psathyrella senex (HMJAU37306) a) Basidiomata b) Basidiosporesc) Basidia d) Pileipellis e) Pleurocystidia f) Cheilocystidia. Bars: a=10 mm, b–f=10 μm. Illustration by Jun-Qing Yan.