Entoloma quadratum (Berk. et M. A. Curtis) E. Horak
Index Fungorum number: IF 313803
Pileus 25—30 mm broad, campanulate with or without an acute papilla, hygrophanous, deep translucently striate, smooth, glabrous, cream, butter yellow to light orange or salmon (4A3—5, 5A3—4, 6A3—4). Lamellae adnate-emarginate, salmon with irregular concolorous edge. Stipe 50—70 3—4 mm, cylindrical or slightly broadened towards the base, longitudinally striate, twisted, concolorous with the pileus or paler, base with white tomentum. Context slightly paler than the surface. Odour and taste indistinct. Spores 7.5—9.3 _ 7.4—8.6 μm, Q = 1.0—1.1, cuboid to subcuboid. Basidia 38.0—49.8 _ 12.1—14.2 μm, clavate, clamped. Lamellae edge sterile. Cheilocystidia in dense clusters, sometimes septate, with narrowly clavate to clavate terminal cells 54.2—101.8 _ 11.6—26.2 μm, colourless or with yellowish contents. Oleiferous hyphae abundant 5—18 μm wide with yellowish granulose contents with hardly differentiated terminal elements. Pileipellis a cutis of cylindrical hyphae 4—12 μm wide. Pigment intracellular. Brilliant granules abundant. Clamp connections present but rare.
Distribution: North America, Russian Far East, Japan, China, Malaysia, Singapore, Borneo, Papua New Guinea, Madagascar (Horak, 1976); Mascarenes (Noordeloos, Hausknecht, 2007); Vietnam.
Collection examined: Vietnam, Lam Dong Prov., Lac Duong Dist., Bidoup-Nui Ba National Park, environs of Klong Lanh village, path to Bidoup Mt, 12°07´37´´ N, 108°39´22´´ E, 1600 m alt., on soil in evergreen mixed forest, 25 June 2010, leg. O. Morozova, LE 262925. — Ibid., Giang Ly Ranger Station, 12°11´08´´ N, 108°40´49´´ E, 1450 m alt., on soil in evergreen mixed forest, 01 July 2010, leg. E. Popov, LE 262924.
Comments: E. quadratum is a well recognizable species due the salmon tint in the colouring of all parts of the basidiome, cuboid spores and distinct acute papilla which often present on the pileus. Our specimens differ slightly from one another in colour (the former is darker) and by the presence of an acute papilla in the second specimen. However, since they are identical microscopically we consider them to be the same species.
Fig. 1 Entoloma quadratum (LE 262924): a spore; b basidium; c cheilocystidia. Bars 10 μm.