Aleurodiscus bambusinus S.H. He & Y.C. Dai

Tian, Yan, Ghobad-Nejhad, Masoomeh, He, Shuang-Hui & Dai, Yu-Cheng, 2018, Three new species of Aleurodiscus s. l. (Russulales, Basidiomycota) from southern China, MycoKeys 37, pp. 93-107 : 95-97

Aleurodiscus bambusinus S.H. He & Y.C. Dai sp. nov. Figs 2 a–b, 3

Diagnosis.

The species is distinct by having corticioid basidiomata, a compact texture, simple-septate generative hyphae, abundant acanthophyses, basidia with an acanthophysoid appendage and smooth basidiospores 7-10 × 4-6 μm and growing on bamboo.

Holotype.

CHINA. Jiangxi Province, Yifeng County, Guanshan Nature Reserve, alt. ca. 800 m, on fallen culms and branches of bamboo, 10 Aug 2016, He 4261 (holotype, BJFC 023703).

Etymology.

“Bambusinus” refers to the substrate of bamboo.

Basidiomata.

Annual, resupinate, effused, closely adnate, inseparable from substrate, coriaceous, at first as small patches, later confluent up to 30 cm long and 2.5 cm wide, 180-300 μm thick. Hymenophore smooth, white (4A1) to yellowish-white (4A2) when young, becoming greyish-yellow [4B (3-4)] to brownish-orange [6C (5-8)] with age, uncracked or cracked with age; margin abrupt, indistinct, concolorous with hymenophore.

Microscopic structures.

Hyphal system monomitic; generative hyphae simple-septate, colourless, thin- to thick-walled, scattered near the substrate, 2-4 μm in diam. Subiculum thin to indistinct. Subhymenium thick, with compact texture, composed of acanthophyses and gloeocystidia. Acanthophyses abundant, hyphoid or distinctly swollen in the middle part, colourless, thin-walled, with abundant spines in apex, 30-40 × 3-12 μm. Gloeocystidia abundant, flexuous or slightly moniliform with one to several constrictions, slightly thick-walled, negative in sulphobenzaldehyde, 30-55 × 8-13 μm. Basidia subclavate to subcylindrical, colourless, slightly thick-walled, usually with a lateral acanthophysoid appendage, with four sterigmata and a basal simple septum, 25-35 × 7-9 μm. Basidiospores ellipsoid to broadly ellipsoid, bearing a dis tinct apiculus, colourless, thin-walled, smooth, amyloid, 7-10 × 4-6 μm, L = 8.7 μm, W = 4.9 μm, Q = 1.6-1.9 (n = 90/3).

Additional specimens examined.

CHINA. Jiangxi Province, Yifeng County, Guanshan Nature Reserve, alt. ca. 800 m, on fallen culms and branches of bamboo, 10 Aug 2016, He 4250 (BJFC 023692) and He 4263 (BJFC 023705).

Remarks.

Aleurodiscus bambusinus is morphologically similar and phylogenetically close to A. dextrinoideophyses S.H. He and A. tropicus L.D. Dai & S.H. He that also grow on bamboo in East Asia ( Dai et al. 2017a, b). Aleurodiscus dextrinoideophyses differs from A. bambusinus by having apparently dextrinoid acanthophyses and smaller basidiospores (5-7 × 3-4 μm, Dai et al. 2017b). Aleurodiscus tropicus differs from A. bambusinus by having a looser texture and slightly larger basidiospores (9-12 × 5-7.5 μm, Dai et al. 2017a). The ITS similarity between A. bambusinus (He 4261) and A. dextrinoideophyses (He 4105) is 95.6% of 434 base pairs and, between A. bambusinus (He 4261) and A. tropicus (He 3830), is 97.3% of 582 base pairs. Aleurodiscus aberrans G. Cunn. and A. rimulosus Núñez & Ryvarden are also similar to A. bambusinus , but they differ from this new species by having smooth basidia and growing on angiosperm wood outside of Asia ( Núñez and Ryvarden 1997).