Aleurodiscus alpinus Sheng H. Wu

Wu, Sheng-Hua, Wei, Chia-Ling, Lin, Yu-Ting, Chang, Chiung-Chih & He, Shuang-Hui, 2019, Four new East Asian species of Aleurodiscus with echinulate basidiospores, MycoKeys 52, pp. 71-87 : 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 Núñez & 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 × 4.5-12.5 μm, thin-walled, guttulate, SA+. Hyphidia numerous, sometimes branched, 40-130 × 2-6.5 μm. Basidia narrowly clavate, occasionally with one or two small protuberances, 85-165 × 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 × 11-14 μm. (22 –)22.2–26(– 27.8) × (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) × (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).

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).