Lulesia umbrinomarginata (Entolomataceae, Agaricales), a newly discovered species from Southern China Author Xiao, Ying-Qun 0009-0003-2851-0256 College of Life Sciences, Hunan Normal University, Changsha 410081, China 202220142775@hunnu.edu.cn Author Xu, You-Di 0009-0004-8112-639X College of Life Sciences, Hunan Normal University, Changsha 410081, China xuyoudi0112@163.com Author Chen, Zuo-Hong 0000-0001-7359-0257 College of Life Sciences, Hunan Normal University, Changsha 410081, China chenzuohong@263.net Author He, Zheng-Mi 0000-0001-8754-3427 College of Life Sciences, Hunan Normal University, Changsha 410081, China zhengmihe@hunnu.edu.cn text Phytotaxa 2024 2024-05-23 650 1 60 72 http://dx.doi.org/10.11646/phytotaxa.650.1.5 journal article 10.11646/phytotaxa.650.1.5 1179-3163 Lulesia umbrinomarginata Y.Q. Xiao, L.Q. Huang & Z.M. He , sp. nov. ( Figs. 2–4 ) MycoBank: MB851831 Etymology:— ‘ umbrinomarginata ’ (Latin), referring to the wood brown pileus margin. Diagnosis:—This species exhibits a brown-hued, zonate, depressed pileus, pale yellow-brown decurrent lamellae, a whitish eccentric stipe with basal rhizoids, white decurrent lamellae, and angular basidiospores. Similar to L . mundula , but differs by its relatively larger basidiospores (6.0–7.0 × 5.0–6.0 μm), which are almost always broadly ellipsoid. FIGURE 2. Lulesia umbrinomarginata . a , b Fresh basidiomes, MHHNU 20022 (holotype); c Dried basidiomes, MHHNU 20023. Bars = 1 cm, photographed by Zheng-Mi He. FIGURE 3. Microscopic features of Lulesia umbrinomarginata (MHHNU 20022, holotype). a Basidiospores; b Basidia; c Pileipellis. Bars = 10 μm, drawn by Ying-Qun Xiao. Type:— CHINA . Guangdong Province : Huidong County, Xunliao Bay, on leaf litter of Acacia confusa Merr. , alt. 20 m , at 22°42'0.07''N , 114°45'3.33''E , 30 June 2023 , Z.M. He 22, MHHNU 20022 ( holotype !). Gene sequences ex-holotype:—PP060629 (ITS); PP059604 (LSU); PP158701 ( RPB2 ); PP158693 ( TEF1 ); PP158697 ( ATP6 ). Description:— Fruitbody small-sized to medium-sized, clitocyboid. Pileus 20–40 mm in diam, applanate with a depressed center; surface dry, greyish brown (4B2-3) to wood brown (5E6-8), zonate, concentric cracked at disc; margin much darker in color, always reflexed to involute, shallowly grooved, undulate to lobate, faintly white (1A1) pubescent at very margin; context thin ( 1–2 mm thick), whitish (2A1). Lamellae decurrent, crowded and often furcate (L = 40–60, I = 1–3), pale yellow-brown (3A2), narrow (about 2 mm high); edges smooth. Stipe 18–23 × 2.5–5 mm , somewhat eccentric, enlarged towards apex and base, often slightly flexuous; surface dry, whitish (2A1), more or less darker in color near apex; base inflated, with many white (1A1) rhizoids; context whitish (2A1). Odor farinaceous. Chemical spot test: surface of dried pileus and stipe produces a red reaction to 5% KOH. Basidiospores [60/3/2] 6.0–7.0 × 5.0–6.0 μm, Q = (1.13–)1.17–1.31(–1.40), Qm = 1.23 ± 0.05, broadly ellipsoid, angular, undulate-pustulate, with acute apiculus (0.7–1.0 μm across), thin-walled, inamyloid, cyanophilic, some of them occurring in tetrads. Basidia 23.0–28.0 ×7.3–9.0 μm, clavate, hyaline, thin-walled, 4-spored; sterigmata up to 5.0 μm long. Pleurocystidia and cheilocystidia absent. Lamellar trama irregular, composed of interwoven, thin-walled, cylindrical hyphae (3.0–)4.0–6.0(–8.0) µm wide. Pileipellis a cutis, composed of parallel to slightly interwoven, slightly thick-walled (up to 0.8 μm), cylindrical hyphae (2.0–)3.0–5.0(–8.0) μm wide, producing a brown intracellular pigment. Stipitipellis a cutis, composed of parallel to subparallel, thin- to slightly thick-walled (up to 0.8 μm) hyphae (3.0–)4.0–6.0(–8.0) μm wide. Clamp connections absent in all tissues. Ecology:—Gregarious, on decaying fallen leave, in subtropical regions; summer. Distribution:—Only known from Southern China . FIGURE 4. Basidiospores of Lulesia umbrinomarginata (MHHNU 20022, holotype) under SEM. Bars = 1 μm, photographed by JianFeng Zou. Additional specimen examined:— CHINA . Guangdong Province : Huidong County, Xunliao Bay, on leaf litter of Acacia confusa , alt. 20 m , at 22°41'59.33''N , 114°45'4.32''E , 30 June 2023 , Z.M. He 23, MHHNU 20023.