Gymnopus pallipes J.P. Li & Chun Y. Deng, 2021

Li, Ji-Peng, Song, Bin, Feng, Zhan, Wang, Jing, Deng, Chun-Ying & Yang, Yi-Hua, 2021, A new species of Gymnopus sect. Androsacei (Omphalotaceae, Agaricales) from China, Phytotaxa 521 (1), pp. 1-14 : 5-7

Gymnopus pallipes J.P. Li & Chun Y. Deng , sp. nov., Figs. 2 & 3

MycoBank:—MB 838798

Typification:— CHINA. Guangdong Province, Xinyi City, Yunkaishan National Nature Reserve , 22° 18’ 06’’ N, 111° 13’ 48’’ E, elev., 1272 m, 21 July 2020, J.P. Li, B. Song ( GDGM 81513 !, holotype) .

Etymology:—The specific name ‘ pallipes ’ (Lat.) refers to the pale stipe.

Diagnosis:—Similar to G. cremeostipitatus , but differs by its glabrous stipe, the presence of pleurocystidia and the absence of caulocystidia; characterized mainly by the pileus becoming paler with age, whitish to pale yellow stipe and presence of rhizomorphs.

Description:— Basidiomata marasmioid. Pileus 5.5–18.5 mm diam, membranous, hemispherical when very young, then convex or with slightly depressed centre, becoming plano-convex to applanate, depressed to umbilicate at the disc, sometimes with small, indistinct papilla in central depression, with deflexed to reflexed, finally more or less undulate margin, dry, hygrophanous, slightly translucently striate at margin, then sulcate when old, dark brown (8F6) overall when very young, then reddish brown (8E6–8) at the disc, paler towards margin (nearly orange-white (5A2) at margin), mostly dull white to yellowish grey (4B2) overall when mature, somewhat cinnamon (6D6) at centre. Lamellae distant, L = 11–20, l = 1–3, up to 2.5 mm broad, adnate, arcuate, or ventricose, sometimes attached to a pseudocollarium, white when young, soon milky white, pale yellow (1A2–1A3) to creamy (4A3) then pinkish (7A2), light brown (6E8) to brown (7E8) and sometimes with brown (7E8) tint in age, white at edge and changing to light brown when mature. Stipe 10–22 mm long, 0.5–2.5 mm thick at the apex, 0.5–1.5 mm thick at the base, centrally attached and instititious, usually tapering at the apex or the base, often cylindrical when young, compressed with age, cartilaginous when young, tough when old, dry, glabrous, white, yellowish white (1A2) to pale yellow (1A3) when young, eye brown (7F6) or paler at apex, generally pastel yellow (3A4) to straw yellow (3B4) overall when mature. Sterile stipes or telepods present, arising near basidiomata with the same characters and colours as normal stipes. Rhizomorphs present, concolorous with stipe, shiny, wiry, simple, repent. Odour negligible.

Basidiospores 5.0–7.0 × 3.0–3.5 μm (average= 6.06 × 3.24 μm, E = (1.43–)1.57–2.17(–2.33), Q=1.88), ellipsoid to oblong. Basidia 20–31.5 × 5.5–6.5 μm, 4-spored, clavate, cylindrical. Basidioles 21.5–31.5 × 5–6.5 μm, clavate, cylindrical. Lamellar edge sterile. Cheilocystidia 11–41 × 2.5–10.5 μm, irregularly clavate, sometimes forked at the upper part, often mostly as Siccus - type broom cells, sometimes only lobed or with less finger-like apical projections (not forming a Siccus - type). Pleurocystidia 18.5–33 × 4–6 μm, fusiform to fusiform-mammilate. Pileipellis a cutis composed of cylindrical hyphae, thin-walled, slightly incrusted, intertwined, hyaline, smooth, up to 14 μm diam; terminal cells often more or less diverticulate, lobed to irregularly branched, sometimes cylindrical, mixed with some having coralloid structure, broom cells not found. Stipitipellis a cutis composed of cylindrical, thin-walled, hyaline, parallel-arranged hyphae, some dextrinoid, otherwise inamyloid, smooth. Caulocystidia absent. Clamp connections present in all tissues.

Ecology:—Saprotrophic, gregarious, usually arising on dead twigs or branches in broadleaf forests.

Additional specimens examined:— CHINA. Guangdong Province, Xinyi City, Yunkaishan National Nature Reserve , 22° 17’ 41’’ N, 111° 13’ 2’’ E, elev., 1490 m, 23 July 2020, B. Song, J.P. Li ( GDGM 82072 ) . Guizhou Province, Qiandongnan Miao and Dong Autonomous Prefecture, Liping Country , near Laidong village , 109° 06’ 53’’ N, 26° 10’ 03’’ E, elev., 662 m, 18 October 2020, J.P. Li & M. Wang ( HGAS-MF 01-10684 ) . Guizhou Province, Qiandongnan Miao and Dong Autonomous Prefecture, Liping Country , near Laidong village , 109° 06’ 53’’ N, 26° 10’ 03’’ E, elev., 662 m, 18 October 2020, J.P. Li & M. Wang ( HGAS-MF 01-10683 ) .

FIGURE. Basidiomata of Gymnopus pallipes . A–B. GDGM 81513 (holotype) C. GDGM 82072 D–E. HGAS-MF 01-10684 F. HGAS- MF 01-10683. Photos by: J.P. Li.

FIGURE. Microscopic features of Gymnopus pallipes (GDGM 81513, holotype!). a. Basidiospores b. Basidia and Basidioles c. Pleurocystidia d. Pileipellis terminal cells e. Cheilocystidia. Scale bars = 10 μm. Drawings by: J.P. Li.