Entoloma longistriatum (Peck) Noordel., Cryptogam.
Pileus 25–40 mm broad, convex, plano-convex expanding to applanate and concave, depressed to umbilicate in the centre, hygrophanous, translucently striate up to 3/4 of the radius and more, finely squamulose in the centre, glabrous to the margin, light brown, yellowish brown (5D4–7) in the centre and in the stripes, paler, greiysh yellow between the stripes (4B4). Lamellae adnate-emarginate or adnate with a decurrent tooth, ventricose, first whitish then beige-pink with an irregular edge concolorous or brownish near the pileus margin. Stipe 50–70 × 3–4 mm, cylindrical or slightly broadened towards the base, fistulose, smooth, glabrous, polished, grayish yellow, yellowish grey, beige to grayish beige (4B2–3, 4C2–3). Context concolorous with the surface or paler. Odour and taste indistinct. Spores 8.0–11.2(11.8) × 6.1–7.9 μm, Q = 1.3–1.6, heterodiametrical with 5–7 angles in side view. Basidia 27.7–32.8 × 10.9–11.5 μm, 2–4-spored, clavate, clampless. Lamellae edge sterile. Cheilocystidia broadly clavate, clavate to subcylindrical, often septate, 27.7–32.8 × 10.9–11.5 μm, colourless. Pileipellis a cutis of repent and slightly ascending hyphae, 5–10 μm wide, with transition to a trichoderm in centre, made up of cylindrical hyphae with inflated terminal elements, 10–20 μm wide, without clamp connections. Pigment brown, intracellular. Oleiferous hyphae and brilliant granules absent.
Distribution: North America (typus); Europe; Siberia, Russian Far East (personal data); Vietnam.
Collection examined: Vietnam, Lam Dong Prov., Lac Duong Dist., Bidoup-Nui Ba National Park, Giang
Ly Ranger Station, 12°11´00´´ N, 108°40´44´´ E, 1450 m alt., on soil in open coniferous forest dominated by Pinus kesiya, 24 June 2010, leg. O. Morozova, LE 262952. Ibid., secondary grassland with signs of recent burning, 26 June 2010, leg. E. Popov, LE 262914.
Comments: Entoloma longistriatum is a typical member of grassland communities of the temperate zone of the Holarctic. The species could be expected to be found in similar habitats in mountain regions of Vietnam. E. longistriatum is a fairly variable species and several varieties have been distinguished. Our specimens possess intermediate characteristics of spores and cheilocystidia, so we couldn’t attribute them to a particular variety.