Lepiota metulispora (Berk. & Broome) Sacc., Syll. fung. (Abellini) 5: 38 (1887).
Index Fungorum number: IF 152336; MycoBank number: MB 152336; Facesoffungi number: FoF 09887; Figs. 1, 2
Pileus 30–65 mm, sub umbonate to umbonate, expanding to plano-concave, with inflexed margin; greyish orange to brownish orange (6B5-8, 6C7-8) glabrous at umbo, with concolorous squamules toward margin on white fibrillose background; margin sulcate, with partial veil remnants, with concolorous squamules on surface. Lamellae free, broadly ventricose, 3–5 mm wide, white, moderately crowded, with 3 length lamellulae, with eroded edge. Stipe 60–80×5–4 mm, cylindrical or slightly tapering to apex, completely fibrillose or cortinate at annular zone, white, with white to greyish orange to brownish orange (6B5-8, 6C7-8) squamules under annular zone downward base, on white to orange-white (5A2) background. Annulus an annular zone, cortinate with white fibrils. Context in pileus white, up to 4 mm wide; in stipe hollow, concolorous with surface. Smell and taste unknown. Spore print white.
Basidiospores [50,2,2] 13–16.5 × 4–5 µm, avl × avw =17.7 × 4.7 µm, Q =2.91–3.30, Qav=3.20, in side-view cylindrical, with attenuate or rounded apex, with straight abaxial side, with an inflexed hilar appendage, with suprahilar depression, fusiform to cylindrical in frontal view, slightly thick-walled, hyaline, dextrinoid, congophilous. Basidia 22–33×7–9 µm, clavate, slightly thick-walled, hyaline, 4-spored. Cheilocystidia 15–35×5–20 µm, clavate to broadly clavate, sometimes utriform, branched or with septate under element cell, thick-walled, hyaline. Pileus covering a trichoderm made up of two layers of element; upper layers made up of cylindrical elements with rounded or attenuate apex, 70–190×5–13 µm, hyaline to pale brown, slightly thick-walled, smooth-walled, with parietal pigment; under layers made up of shortly clavate to clavate elements, 35–50×8–14 µm, smooth or rough-walled, with hyaline to parietal pale brown pigment. Stipe covering of squamules similar to pileus covering. Clamp connections present.
Material examined – Laos, Oudomxay Province, Xay District, Houay Houm Village, N 20° 32′ 00.67″, E 101° 53′ 48. 17.16″. 917 m., 15 June 2014, P. Sysouphanthong, PS2014- 1465 (HNL503136); ibidem, 20 July 2014, P. Sysouphanthong, PS2014-1480 (HNL503151).
Habitat and distribution – solitary or grow in a small cluster with few basidiomes, on dead leaves and humus soil, saprotrophic. The species was only reported from tropical regions viz. Sri Lanka (Pegler 1972), India (Kumar and Manimohan 2009), China and Hong Kong (Liang et al. 2011), Tanzania (Pegler 1977), Thailand (Sysouphanthong et al. 2012). This is the first report of L. metulispora in northern Laos.
GenBank numbers – HNL503136–MT436261 (ITS). HNL503151–MT436262 (ITS).
Notes – Lepiota metulispora has a trichodermal pileus covering and penguin-shaped basidiospores, and it is placed in the section Lepiota (Vellinga 2001). The species is widespread in tropical countries. Lao specimens were found in the mature stage, colour of squamules on pileus is paler than Thai specimens, but the morphology is identical (Sysouphanthong et al. 2012). The type specimen of the species from Sri Lanka is closer to Lao and Thai specimens in morphology, but basidiospores are slightly larger and cheilocystidia are undetermined (Pegler 1972). Liang et al. (2011) studied the type material from Sri Lanka and compared it with the Chinese specimen, and the type specimen has a smaller basidiospore size. However, it seems that the size of basidiospores is not much different in all specimens found in China, Laos, Sri Lanka and Thailand; and the morphology and size can be minorly different in different specimens. According to the analysis of nrITS sequence data (Fig. 2), Lao specimens are identical to specimens from China with high (100%) bootstrap support.
Lepiota thrombophora from Thailand is most similar to L. metulispora in morphology, but differ in smaller basidiospores size (10–14×3–5 μm) (Hyde et al. 2021); and the type specimen of L. thrombophora from Sri Lanka is different in dark brown squamules on pileus and shorter elements of pileus covering (25–100×5–15 µm). Liang et al. (2011) described L. thrombophora from China, based on its longer elements (up to 330 µm long). The analysis of nrITS sequence data showed that Chinese and Thai specimens of L. thrombophora are identical, and related to L. metulispora (Fig. 2). The type specimen of L. attenuata from China is closer to L. metulispora in morphology but differs in much longer elements on pileus covering (231 µm long), and basidiospores are more attenuated at the apex (Liang et al. 2011). Thai specimens of L. attenuata from Thailand have longer and typically attenuate elements (300 µm long) (Hyde et al. 2021). Other similar species to L. metulispora were discussed in Sysouphanthong et al. (2012).
Figure 1 – Lepiota metulispora in habitat. a-c HNL503136 d-e HNL503151
Figure 2 – Lepiota metulispora (HNL503151, new record). a Basidiospores b Cheilocystidia c Pileus covering
Figure 3 – Maximum likelihood phylogenetic tree based on nrITS sequences of Lepiota species. Bootstrap support≥70% is indicated at the nodes. New sequences from this study are in blue. The GenBank accession numbers are indicated after the species name. Abbreviation L=Lepiota, M=Macrolepiota. The tree is rooted in Macrolepiota orientiexcoriata