Three new species of Micropsalliota (Agaricaceae, Basidiomycota) from central and southern Vietnam Author Ivanova, Daria 0000-0002-8302-8337 Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Str., 2, 197376 St. Petersburg, Russia & divanova @ binran. ru; https: // orcid. org / 0000 - 0002 - 8302 - 8337 divanova@binran.ru Author Morozova, Olga 0000-0002-7329-528X Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Str., 2, 197376 St. Petersburg, Russia & omorozova @ binran. ru; https: // orcid. org / 0000 - 0002 - 7329 - 528 X omorozova@binran.ru Author Pham, Thi Ha Giang 0000-0002-4137-7213 Joint Vietnam-Russia Tropical Science and Technology Research Centre, Nguyen Van Huyen, Nghia Do, Cau Giay, Hanoi 122100, Vietnam & giangvietnga @ gmail. com; https: // orcid. org / 0000 - 0002 - 4137 - 7213 giangvietnga@gmail.com text Phytotaxa 2023 2023-11-28 626 4 247 258 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.626.4.2/51317 journal article 10.11646/phytotaxa.626.4.2 1179-3163 10212911 Micropsalliota suricatoides D.D. Ivanova, O.V. Morozova & T.H.G. Pham , sp. nov. ( Fig. 5 ) Mycobank: MB849328 Type:— VIETNAM , Dong Nai Province : Vinh Cuu District, Dong Nai Cultural and Nature Reserve, tropical polydominant mixed forest, on soil, 13.06.2011 , coll. O . V . Morozova , 280 VN 11 ( holotype : LE F-348072!, isotype : VRTC !). Etymology:—Referring to beige clusters of basidiomata with fine fibrillose squamules on caps that remind mobs of meerkats ( Suricata suricata ). Diagnosis:—This species is characterized by having small size of beige basidiomata, staining yellow when bruised, pileus with brown squamules, utriform and lageniform cheilocystidia, and stipitipellis hyphae with capitate apices. Description: Basidiomata small, beige when fresh, yellow when bruised (3 B 7–8), discoloring to light brown (6D4), brown (6 E 6–4) or dark brown (6 F 4–7) when dried. Pileus 4–13 mm in diameter, campanulate when young, convex when mature; surface dry, beige, brownish orange, greyish orange (5 C 3, 5 B 3), squamulose, darker towards the center due to presence of fine, fibrillose, brown (7 E 8–5) squamules which are located denser in the center; margin white or beige, fibrillose; the surface reddish brown (8 E 4) in KOH. Lamellae free, crowded, 1 mm broad, cream, intercalated with lamellulae. Stipe 16–28 × 0.5–1 mm , cylindrical, greyish brown (6D3) or brownish beige (6 E 3); covered with tiny white fibrillose scales. Annulus persistent, pendent, single, white or concolorous with the pileus. Basidiospores (4.2–)5.4–6.7 × (2.7–)3.2–4.5 µm, Q = 1.31–1.82, Q m = 1.6 (n = 21), amygdaliform in side view, ellipsoid in frontal view, with apical endosporal thickening. Basidia (12–)13.6–14.8(–16.9) × 5.4–6.9 µm, clavate, 2- and 4-spored, hyaline. Cheilocystidia (13.7–)19.5–22.0(–30.2) × (5.1–)9.3–8.8(–13.5) µm, utriform and lageniform, necks and capitula absent. Pleurocystidia absent. Pileipellis a cutis, composed of hyphae 5–8(–10) µm, constricted at the septa, incrusted with brownish pigment. Stipitipellis of cylindrical hyphae 5–8 μm wide, many with capitate apices. Habitat and distribution:—In small groups on soil in tropical evergreen mixed forest. Known only from the type locality in southern Vietnam . Additional specimens examined: VIETNAM , Dong Nai Province :Vinh Cuu District, Dong Nai Cultural and Nature Reserve, tropical polydominant mixed forest, on soil, 14 June 2011 , coll. O . V . Morozova LE F-348071 (303 VN 11). Gia Lai Province : K’Bang District, Son Lang Commune, Kon Chu Rang Nature Reserve, polydominant evergreen broadleaf, mixed (dominated by trees from Podocarpaceae , Theaceae , Magnoliaceae , Fagaceae , Hamamelidaceae , Lauraceae , Burseraceae , Myrtaceae , Clusiaceae , Fabaceae ) and coniferous (dominated by Dacrydium elatum ) forest, 14°28’09.9”N 108°32’24.8”E , elevation 923 m , on soil, 28 October 2022 , LE F-348070 (209 NVP 22), coll. N . V . Psurtseva ; 27 October 2022 , coll. V . A . Dudka , LE F-348069 (222 VN 22). Notes: Micropsalliota suricatoides is characterized by having small basidiomata, basidiomata staining yellow when bruised, beige pileus with brown squamules, utriform and lageniform cheilocystidia, pileipellis hyphae with brownish pigment and stipitipellis hyphae with capitate apices. Two of the specimens from Vietnam has a distinguishable dark umbo ( LE F-348070 and LE F-348069). Micropsalliota brunneola Heinem. possesses a larger ( 20-30 mm in diameter) brown squamulose pileus without umbo, smaller spores (4.1–4.9 × 2.9–3.3 μm), much broader pileipellis hyphae of 8–20 μm in diameter ( Heinemann 1980: 46 ). Micropsalliota allantoidea R.L. Zhao, Desjardin, K. Soytong & K. D. Hyde shares scaly convex pileus, but has brown lamellae, ventricose-capitate cheilocystidia and pileipellis hyphae 8–17 μm in diameter ( Zhao et al. 2010: 15 ). Micropsalliota megaspora R.L. Zhao, Desjardin, Soytong & K.D. Hyde has larger spores (6–8 × 3.8–4.5 μm), ventricose to pyriform cheilocystidia, broader pileipellis hyphae 10–22 μm in diameter. ( Zhao et al. 2010: 64 ). Micropsalliota brunneosquamata L.J. Chen, R.L. Zhao & K.D. Hyde possesses much bigger basidiomata (pileus 31–40 mm in diameter), stipe heavily covered by brown fibrils under annulus with bulbous base, cheilocystidia various in shape, and broader pileipellis hyphae 5–25μm diameter ( Chen et al. 2016: 692 ).