Micropsalliota ovalispora J. Q. Yan sp. nov.
MycoBank: 842892
Etymology: Referring to its oval basidiospores in face view.
Diagnosis: Differs from M. arginea in having ovoid basidiospores. (Figures 2D, 4, 10B)
Basidiomata slender to stout (IG = 22–62). Pileus 5.0– 7.0 mm in diameter, white (1A1), orange-gray (6B2) with age, convex, expanding to plane, with obtuse umbo, surface dry, glabrous to fibrillose. Context less than 0.5 mm thick. Lamellae 0.5–0.7 mm broad, free, moderately distant, with 2 series of lamellulae, white (1A1) becoming light brown (7D5–7D6) as mature. Stipe 7.5–12.5 × 0.5–1.0 mm, cylindrical, white (1A1), surface with white (1A1) fibrils. Annulus unobserved.
Basidiospores 4.0–5.0 × (2.0) 2.5–3.0µm, av. = 4.5 × 2.7µm, Q = (1.43) 1.55–1.85 (2.00), oval, rarely ellipsoid to elongate in face view, amygdaliform in profile view, light brown in water, darker in alkaline solution, wall 0.2–0.3µm thick, apically thickened endosporium indistinct, without germ pore, inamyloid. Basidia 12.5–18.5 × 5.0–6.5µm clavate, hyaline, 4- spored. Pleurocystidia absent. Cheilocystidia (22) 25.5–40 (42) × 4.0–8.5 (10.5) µm, lageniform, apex capitate, (4.0) 5.0– 7.5 (8.0) in diameter. Pileipellis a cutis, hyphae 4.5–11µm in diameter, constricted at the septa on some hyphae, with small dark brown incrusted pigment granules in water, which dissolves in 5% KOH.
Habit and habitat: Scattered on soil in broad-leaved forests.
Specimens examined: CHINA. Zhejiang Province, Lishui City, Suichang County, Jiulong Mountain Reserve, 15 Jul 2020, Jun-Qing Yan, HFJAU2010, holotype; 17 Jul 2020, Jun-Qing Yan and Bin-Rong Ke, HFJAU3179.
Notes: In the phylogenetic tree, M. ovalispora formed an independent lineage and grouped with M. allantoidea, but the latter has a grayish brown pileus and longer basidiospores (5.3– 6.5µm) (Zhao et al., 2010). Morphologically, only a few other species in the genus match the characteristics of M. ovalispora. Micropsalliota arginea, M. cinnamomeopallida Singer, M. plumeria (Berk. and Broome) Höhn., M. pseudoarginea Heinem., and M. tenuipes are similar to M. ovalispora in having a white pileus and 5.0–10µm in diameter, but none of them have oval basidiospores (Pegler and Rayner, 1969; Heinemann, 1980; Heinemann and Leelavathy, 1991; Zhao et al., 2010). In addition, M. arginea, M. pseudoarginea, M. ovalispora, and M. tenuipes are in distinct lineages in the phylogenetic tree (this paper); pileipellis of M. cinnamomeopallida has brownish vacuolar pigment (Heinemann, 1980; Heinemann and Leelavathy, 1991); pileus of M. plumeria has rusty brown disc (Zhao et al., 2010)
参考翻译：
卵孢小蘑菇 新物种 Micropsalliota ovalispora J. Q. Yan sp. nov.
MycoBank编号：842892
词源：种加词ovalispora指其背腹观卵形的担孢子。
该物种和M. pusillissima的区别是本种的担孢子更大，长度超过5μm。
担子果细瘦至粗壮（IG=22-62）。菌盖宽5.0-7.0mm，白色，成熟后变橙灰色，凸镜形，逐渐平展，中部有钝凸起，盖表干，光滑至纤维状。菌肉不到0.5mm厚。菌褶0.5-0.7mm宽，离生，较稀疏，小菌褶2轮，白色，成熟变浅褐色。菌柄7.5–12.5 × 0.5–1.0 mm，圆柱形，中空，白色，被白色小纤维。菌环未观察。
担孢子4.0–5.0 × (2.0) 2.5–3.0µm，平均长宽av. = 4.5 × 2.7µm，长宽比Q = (1.43) 1.55–1.85 (2.00) ，背腹观卵形，很少椭圆形或长椭圆形，侧面观杏仁形，H2O中浅褐色，碱性溶液中颜色更深，孢壁0.2-0.3μm厚，内孢壁顶端不明显加厚，无芽孔，非淀粉质。担子12.5–18.5 × 5.0–6.5µm，棒状，透明，4小梗。侧生囊状体阙如。褶缘囊状体(22) 25.5–40 (42) × 4.0–8.5 (10.5) µm，烧瓶形，顶端头状膨大，宽(4.0) 5.0– 7.5 (8.0)μm。菌盖皮层表皮型（cutis），由宽4.5–11µm的菌丝组成，H2O中有小的结痂状色素颗粒，在5%KOH中这些颗粒溶解，部分菌丝在隔膜处溢缩。
生境与分布：散生在阔叶林地表。
研究标本: CHINA. Zhejiang Province, Lishui City, Suichang County, Jiulong Mountain Reserve, 15 Jul 2020, Jun-Qing Yan, HFJAU2010, 主模式；17 Jul 2020, Jun-Qing Yan and Bin-Rong Ke, HFJAU3179.
讨论：卵孢小蘑菇在系统发育树上形成了单独的一个分支，且和M. allantoidea构成姊妹群，但后者有灰褐色的菌盖和更长的担孢子(5.3– 6.5µm)。形态学上，仅少数几个小蘑菇属物种近似于卵孢小蘑菇。M. arginea、M. cinnamomeopallida、M. plumeria、M. pseudoarginea、M.tenuipes同样拥有白色菌盖，和宽5-10μm的
#原文中作者漏写了一个单词，猜测可能是褶缘囊状体末端头状膨大# ，但它们都没有卵形的担孢子。另外，M. arginea、M. pseudoarginea、卵孢小蘑菇M. ovalispora和M. tenuipes（本文中）处在系统发育树上不同的支系；M. cinnamomeopallida盖皮有褐色色素；M. plumeria的菌盖有锈褐色的中心。
