Four new East Asian species of Aleurodiscus with echinulate basidiospores Author Wu, Sheng-Hua Author Wei, Chia-Ling Author Lin, Yu-Ting Author Chang, Chiung-Chih Author He, Shuang-Hui text MycoKeys 2019 52 71 87 http://dx.doi.org/10.3897/mycokeys.52.34066 journal article http://dx.doi.org/10.3897/mycokeys.52.34066 1314-4049-52-71 Aleurodiscus alpinus Sheng H. Wu sp. nov. Figs 2A, 3 Typification. CHINA. YUNNAN PROVINCE: Shangrila County, Pudacuo National Park, Bita Lake, 27°43'N , 99°58'E , 3640 m, on branch of Rhododendron sp., 10 Jul 2014, S.H. Wu, Wu 1407-55 (holotype TNM F27976). GenBank 28S = MF043526, TEF1 = LC269190. Etymology. alpinus (L.), referring to the occurrence at high elevations. Diagnosis. Resembles Aleurodiscus cupulatus Nunez & Ryvarden in having discoid basidiomes, clamped hyphae, similar gloeocystidia, absence of acanthophyses, branched or unbranched hyphidia, and echinulate basidiospores. Aleurodiscus cupulatus features much wider basidiospores than A. alpinus . It differs from its closest phylogenetic relative, A. sichuanensis , by having clamped hyphae, but lacks acanthophyses. Description. Basidiomes cupuloid or discoid, solitary, occasionally fused, adnate, 350-750 μm thick in section. Hymenial surface Buff, Pale Luteous or Luteous, subceraceous, covered with crystal masses, not cracked; margin concolorous or paler, incurved, filamentous. Hyphal system monomitic; hyphae nodose-septate. Pileus hyphae subcolorless to brownish, straight, thick-walled, walls usually thinner towards apices, usually with excreted material near apices. Subiculum uniform, with dense to compact texture, 150-500 μm thick; hyphae near substrate more or less vertical, moderately ramified, colorless, 3.5-8 μm diam, with 0.7-1.5 μm thick walls, occasionally guttulate; hyphae near hymenial layer more or less vertical, moderately ramified, colorless, fairly straight, 2.5-5 μm diam, thin- or slightly thick-walled, anastomoses occasional. Hymenial layer thickening, subhymenium differentiated from subiculum, 200-250 μm thick, with dense texture; hyphae fairly vertical, colorless, guttulate, 2-4 μm diam, thin-walled. Crystals sparsely scattered throughout section. Gloeocystidia numerous, immersed or slightly projecting, tubular, sometimes with adventitious septa near basal parts, colorless, (50 -)70- 200 x 4.5-12.5 μm , thin-walled, guttulate, SA+. Hyphidia numerous, sometimes branched, 40-130 x 2-6.5 μm . Basidia narrowly clavate, occasionally with one or two small protuberances, 85-165 x 16-20 μm , slightly thick-walled (ca. 0.5 μm thick), 4-sterigmate. Basidiospores ellipsoid to narrowly ellipsoid, adaxially concave, finely aculeate, thin-walled, homogenous or guttulate, amyloid, CB- , mostly 22-26 x 11-14 μm . (22 -)22.2-26(- 27.8) x (11 -)11.8-13.5(- 14.8) μm , L = 24.2 +/- 1.7 μm , W = 12.6 +/- 2.2 μm , Q = 1.95 (n = 30) (holotype, Wu 1407-55); (22 -)23-24.5(- 26) x (10.2 -)10.8-13(- 14) μm , L = 23.8 +/- 1.0 μm , W = 11.8 +/- 1.0 μm , Q = 2.02 (n = 30) (Wu 1407-59). Figure 2. Basidiocarps A Aleurodiscus alpinus (holotype, Wu 1407-55) B A. pinicola (holotype, Wu 1308-54) C A. senticosus (holotype, Wu 1308-54) D A. sichuanensis (holotype, Wu 0010-18). Ecology and distribution. On dead branches of Rhododendron and other angiosperms at very high elevations, China, Jul. Additional specimens examined. CHINA. YUNNAN PROVINCE: Shangrila County, Pudacuo National Park, Bita Lake, 27°43'N , 99°58'E , 3640 m, on branch of Rhododendron sp., 10 Jul 2014, S.H. Wu, Wu 1407-59 (TNM F27979), Wu 1407-61 (TNMF27981); Pudacuo National Park, 3600 m, on dead branch of Rhododendron sp., 28 Jul 2017, S.H. He, He 4924 (BJFC), He 4942 (BJFC); Jianchuan County, Laochunshan, 26°38'N , 99°47'E , 3400 m, on angiosperm branch, 26 Jul 2001, S.H. Wu & S.Z. Chen, Wu 0107-22 (TNMF13507), Wu 0107-25 (TNMF13510). Figure 3. Microscopic structures of Aleurodiscus alpinus (holotype, Wu 1407-55) A profile of basidiocarp section B subhymenial and hymenial section C basidiospores (far right: in IKI) D subicular hyphae near substrate E pileus hyphae F subhymenial hyphae G hyphidia H branched hyphidia I gloeocystidia J basidia. Bars: 300 μm (A); 10 μm ( B-J ).