Lepiota venenata

MycoBank number: MB 824765; IndexFungorum number: IF 824765; Facesoffungi number: FoF 10409;

Description

Pileus 17-20 mm diam., first parabolic, expanding to umbonate with high umbo, with inflexed margin; fibrillose squamules and squamules at umbo towards margin, light brown to brown (7D6-8), slightly darker at umbo, on white fibrillose background; marginal zone with brown concolorous fibrillose squamules and white thin fibrillose. Lamellae free, crowded, ventricose, 2-3 mm wide, white, with concolorous eroded edge. Stipe 25-32 × 3-4 mm, cylindrical, with slightly tapering to apex; covered with light brown to brown (7D6-8) squamules from annular zone toward base on white background. Annular an annular zone, with white fibrillose and concolorous squamules. Context white in pileus, 1.5-2 mm wide; white and hollow in stipe. Smell and taste not observed. Spore print white.

Basidiospores [50,1,1] 5.5-7.5 × 3.5-4.5 µm, avl × avw = 6.5 × 4.0 µm, Q=1.5-1.8, Qav= 1.6, oblong ovoid in side view, oblong in frontal view, hyaline, slightly thick-walled, dextrinoid, congophilous, cyanophilous, not metachromatic in Cresyl Blue. Basidia 15-18× 5.0-6.5 µm, clavate, thin-walled, hyaline, 4-spored. Pleurocystidia absent. Cheilocystidia 15-25 × 5.0-8.0 µm, mostly clavate, often utriform, rarely cylindrical, hyaline, thin-walled. Pileus covering a trichoderm made up of cylindrical elements, always tapering to apex, 55-275 × 6.0-13 µm, slightly thick-walled, with brown intracellular and parietal pigment, without short clavate or clavate elements under long elements, branched and septate. Clamp connections present in all tissues.

Material examined Laos, Xekong Province, Tha Teng District, 30 September 2015, P. Sysouphanthong (HNL503248).

GenBank numbers: ITS: MZ717724 (ITS1-F/ITS4).

Habitat and distribution grow solitary to a small group, terrestrial on rich humus soil, found in China and Laos (Cai et al. 2018).

Notes Lepiota venenata was originally described from Hubei Province of China (Cai et al. 2018). The type specimen from China differs from the Lao specimen by having larger basidiomata (30-60 mm diam. of pileus), brown to reddish brown squamules on pileus and stipe, white to cream lamellae, longer cheilocystidia (20-38 µm). However, other characters are similar. The phylogenetic three showed that Lepiota venenata is identical to those specimens from China (Cai et al. 2018) and a specimen from Thailand (JN224862, unpublished). The species is placed in the clade of Lepiota sect. Ovisporae consists of species with long elements of pileus- and stipe coverings without short clavate elements, and Lepiota sect. Stenosporae. A single collection Lepiota venenata was collected from southern Laos, and it has similar morphology with type specimens from China (Cai et al. 2018).

Fig. 1 Basidiomata of Lepiota venenata in situ. (new country record). a–c (HNL503248).

Fig. 2 Microcharaters of Lepiota venenata (HNL503248).  a Basidiospores. b Cheilocystidia. c Elements structure on pileus covering.