Micropsalliota globocystis Heinem., Bull. Jard. Bot. natn. Belg. 50(1–2): 57 (1980)

Index Fungorum number: IF 113558; MycoBank number: MB 113558; Facesoffungi number: FoF 09760; Figs. 1, 2

Pileus 30–70 mm diam., when young subglobose to broadly conical, expanding to convex or umbonate, applanate to plano-concave when mature, with straight margin, surface fibrillose to squamules fibrillose, reddish brown (9D4-8), darker at center, on white to pale yellow (5A3) fibrillose background, turning orange white (5A2) when touched, margin with sulcate marginal zone, with exceeding lamellae when mature. Lamellae free, ventricose, up to 5 mm wide, white to yellowish white (4A2) at first, becoming orange grey to greyish orange (6B2-3) when mature, crowded, with white eroded lamella-edge. Stipe 50–100×5–8 mm, cylindrical, or slightly wider at base; surface covered with white fibrillose, crowded, on white fibrillose background, turning orange-white (5A2) when touched. Annulus superior, persistent, white. Context in pileus white, in stipe white and hollow, when cut turning orange white (5A2) in both stipe and pileus context. Taste and oduor not observed. Spore print orange grey (6B2). Basidiospores [50,2,2] 5.5–8.5×3–4 µm, avl×avw =6×4 µm, Q =1–2, Qav=1.5, ellipsoid in side-view, ellipsoid to oblong in frontal view, without germ pore, slightly thick-walled, hyaline to pale brown. Basidia 15–23×7–10 µm, clavate, hyaline and slightly thick-walled, 4-spored. Cheilocystidia abundant, 28–65×7–16 µm, narrowly clavate to broadly clavate, sometimes with median constriction and 1–2-septate, hyaline, thick-walled. Pleurocystidia absent. Pileus covering a cutis made up of cylindrical elements, 60–110×10–23 µm, encrusted, with reddish brown parietal and intracellular pigment, with encrusted hyphae in lower layer, hyaline or with reddish brown parietal and intracellular pigment. Stipe covering not observed.

Material examined – LAOS, Xiangkhouang Province, Koun District, Om Village, 27 May 2016, P. Sysouphanthong, PS2016-69 (HNL501440); Oudomxay Province, Beng District, Na Pa Village, 23 June 2014, P. Sysouphanthong, PS2014-106 (HNL501777, new record).

GenBank numbers – ITS=MW073388, MW073389.

Notes – Micropsalliota globocystis is a saprotrophic species found in the northern part of Laos (Figs. 1 and 2). Zhao et al. (2010) indicated that the species is very common in Thailand. Molecular analysis showed that M. globocystis is sister to M. megarubescens, but they are quite different in morphology. Another species, M. pseudoglobocystis also resembles to M. globocystis, but the cheilocystidia vary in shape. Molecular analysis confirmed that they are distinct species (Wei et al. 2015). According to the nrITS analysis, the M. globocystis complex includes M. globocystis, M. pseudoglobocystis and M. pseudoglobocystis. Lao specimens of M. globocystis grouped well with those from Thailand and China (Fig. 3). Both morphology and molecular data derived from Lao and Thai specimens indicate that they are conspecific.

Figure 1 – Micropsalliota globocystis (HNL501777, new record). a, b Basidiomata

Figure 2 – Microcharacters of Micropsalliota globocystis (HNL501777). a Basidiospores. b Cheilocystidia. c Element cells at pileus covering. Scale bars: a=5 µm, b=10 µm, c=20 µm

Figure 3 – Maximum likelihood phylogenetic tree of Micropsalliota based on nrITS sequences. The maximum likelihood (ML) analysis was performed in RAxML 7.2.6 (Stamatakis et al. 2008) and maximum parsimony (MP) analysis was performed the program PAUP* 4.0 b10 (Swofford 2004). Bootstrap values of ML/MP equal to or greater than 70% are given above branches. GenBank accession number is indicated after species name. Leucoagaricus meleagris (MT252565) is an outgroup. Newly sequences generated from Laos are in blue