Psathyrella gordonii (Berk. & Broome 1861: 377) A. Pearson & Dennis (1948: 184)

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 gordonii (Berk. & Broome 1861: 377) A. Pearson & Dennis (1948: 184) Figs. 1c , 4

= Psathyrella pervelata Kits van Wav. (1971: 309)

= Psathyrella vestita ( Peck 1906: 28) A.H. Sm. (1941: 58)

Description:— Pileus 4–16 mm, in early stage with dirty white (5A1–5B2) margin and light brown (7C4) center, hemispherical to subcampanulate, veil is strongly developed and covers the pileus with white (7A1) floccules and fibrils, evanescent; at maturity gray-white (7A1–7B2), center light brown (7C3–7C4), conical, obtuse at center. Context thin, white (7A1) and fragile. Lamellae to 2.0 mm broad, close, thin, adnate, unequal, gray to dark gray-brown (6D1–6D3), edges white (6A1), even. Stipe 14–42 mm long, 1.5–2 mm thick, white, cylindrical, hollow, fragile, with sub-bulbous base, covered with white (7A1), evanescent, floccose fibrils. Odour and taste indistinct. Spore print not recorded.

Spores 8.3–9.9 × 3.9–4.9 μm, Q=1.8–2.3, elongated-ellipsoid to subcylindrical, dark brown in 5% KOH, inamyloid, smooth, germ pore distinct, 1.8–2.3 μm in diam. Basidia 19–22 × 9.8–10 μm, 4 or 2-spored, clavate, hyaline in 5% KOH. Pleurocystidia scattered, 34–46 × 9.8–12 μm, utriform with obtuse apex. Cheilocystidia 29–41(48) × 8.5–9.8(11) μm, utriform to narrowly utriform. Caulocystidia similar to cheilocystidia, 31.7–48.7 × 8.5–9.8 μm, but caespitose and scanty. Trama of gills parallel hyphae, hyaline. Pileipellis a 3–4 cells deep layer of vesiculose hyphae, 29–48 μm in diameter. Clamps present.

Habit and habitat:—Gregarious to caespitose on decaying roots of poplars.

Known distribution:—Baltic States ( Urbonas et al. 1986), Canada ( Smith 1972), China, Finland, France ( Kühner & Romagnesi 1953), Germany, Northern Ireland ( Kits van Waveren 1985), Sweden ( Örstadius et al. 2015), United Kingdom of Great Britain ( Kits van Waveren 1985) and United States of America ( Smith 1972).

Material examined:— CHINA. Jilin Province: Jilin Agricultural University, Changchun City, 6 September, 2015, Tolgor Bau HMJAU35983 ; 8 September, 2015, Jun-Qing Yan HMJAU35984 (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 4. Psathyrella gordonii (HMJAU35983) a) Basidiomata b) Basidiospores c) Basidia d) Pileipellis e) Cheilocystidia f) Pleurocystidia g) Caulocystidia. Bars: a=10 mm, b–g=10 μm. Illustration by Jun-Qing Yan.