Entoloma myriadophyllum

Entoloma myriadophyllum O. V. Morozova

Pileus 22—40 mm broad, 1.5—2.3 mm high, hemisphaerical or campanulate with deeply depressed to umbilicate center, with irregularly undulating margin, slightly hygrophanous, not translucently striate, smooth, glabrous, grayish yellow (4B3—5) to pale yellow (3A3, 4A3), yellowish white (3A2, 4A2) towards margin. Lamellae arcuate, subdecurrent, very narrow, up to 2 mm wide, very crowded, 50—65 reaching the stipe, first whitish then yellowish white to orange white (3A2, 4A2, 5A2) with entire concolorous edge. Stipe 80— 100 6—10 mm, cylindrical, broadened towards the base, or fusiform, fistulose, brittle, longitudinally fibrillose, yellowish white (3A2, 4A2). Context whitish. Odour and taste farinaceous. Spores 8.0—9.8 5.6—7.0µm, Q=1.3—1.4, heterodiametrical with 5—7 angles in side view. Basidia 30.8—40.7 10.4—13.0 µm, clavate, clamped. Lamellae edge heterogeneous. Cheilocystidia 30.9—51.8 5.6—11.5 µm, clavate to subfusiform, often septate, as chains of inflated elements, colourless. Hymenophoral trama regular, made up of cylindrical to subfusoid elements, 30—70 5—18 µm. Pileipellis a cutis of repent and slightly ascending hyphae, 3—8 µm wide, with subpellis made up of inflated elements, 42—83 15— 21 µm, without clamp connections. Pigment both intracellular and finely encrusting. Oleiferous hyphae present in pileitrama, but rare. Brilliant granules absent.

Distribution: Vietnam (typus).

Additional collections examined: Vietnam, Lam Dong Prov., Lac Duong Dist., Bidoup-Nui Ba National Park, Hon Giao Ranger Station, path to Hon Giao Mt, 12°11´32´´ N, 108°42´40´´ E, 1850 m alt., upper montane mossy evergreen broadleaf forest, caespitose on soil, 14 November 2011, leg. A. Kovalenko, Yu. Novozhilov, LE 253831. Comments:Entoloma myriadophyllum is a remarkable species due to it’s extremely narrow and crowded lamellae. Caespitose growth is also uncommon in Entoloma. The structure of the pileipellis led to its placement in the subgenus Entoloma, where it occupies a rather isolated position. On account of the depressed to infundibuliform pileus it shows much resemblance to the members of section Polita Noordel., although the presence of encrusting pigment is not characteristic of this section. E. clitocyboides E. Horak et Singer from Brazil seems to be close, however differs by white and less depressed pileus with differently shaped lamellae, differently shaped cheilocystidia and completely lacking clamps. E. subinfundibuliforme T. H. Li et Chuan H. Li and E. subclitocyboides W. M.Zhang originally described from China are characterized by more robust basidiomata with more broad and distant lamellae and absence of clamp connections in all hyphae. E. angustifolium Murrill, a North American species with narrow and crowded lamellae, possesses convex pileus, solid glabrous stipe and larger spores.