Alloexidiopsis grandinea J. H Dong & C. L. Zhao, 2024

Dong, Junhong, Zhu, Yonggao, Qian, Chengbin & Zhao, Changlin, 2024, Taxonomy and phylogeny of Auriculariales (Agaricomycetes, Basidiomycota) with descriptions of four new species from south-western China, MycoKeys 108, pp. 115-146 : 115-146

Alloexidiopsis grandinea J. H Dong & C. L. Zhao sp. nov.

Figs 10 , 11 , 12

Diagnosis.

Differs from other Alloexidiopsis species by its membranaceous basidiomata with buff to slightly yellowish, grandinioid hymenial surface, a monomitic hyphal system with clamped generative hyphae and cylindrical to allantoid basidiospores measuring 10–12.3 × 5–5.8 µm.

Holotype.

China • Yunnan Province, Zhaotong, Wumengshan National Nature Reserve , 28 ° 03 ′ N, 104 ° 20 ′ E, altitude 1500 m, on the fallen branch of angiosperm, leg. C. L. Zhao, 21 September 2023, CLZhao 33798 ( SWFC).

Etymology.

grandinea (Latin or Greek origin): referring to the grandinioid hymenial surface.

Basidiomata.

Annual, resupinate, closely adnate, membranaceous, very hard to separate from substrate, without odour or taste when fresh, becoming coriaceous upon drying, up to 20 cm long, 3 cm wide, 50–100 µm thick. Hymenial surface grandinioid, white to buff when fresh, turning to buff to slightly yellowish upon drying. Sterile margin cream to buff, thinning out, up to 1 mm wide.

Hyphal system.

Monomitic, generative hyphae with clamp connections, colourless, thin-walled, rarely branched, interwoven, 2–4 µm in diameter; IKI –, CB –, tissues unchanged in KOH. Hymenium. Cystidia numerous, thin-walled, fusiform with an acute apex, occasionally sinuous in the basal, 20–42.5 × 5.5–9.5 µm, with a clamp connection at base; cystidioles absent. Hyphidia arising from generative hyphae, nodulose, frequently branched, colourless, thin-walled, 2–5 µm in diameter. Basidia ellipsoid to ovoid, longitudinally septate, two to four-celled, 12.5–14.5 × 9–11.5 µm; basidioles dominant, similar to basidia in shape, but slightly smaller. Basidiospores. Cylindrical to allantoid, slightly curved, colourless, smooth, thin-walled, with 1–2 oil drops, IKI –, CB –, (9.5 –) 10–12.3 (– 12.5) × (4.8 –) 5–5.8 (– 6) µm, L = 11.08 µm, W = 5.38 µm, Q = 1.95–2.20, Q m = 2.06 ± 0.04 (n = 60 / 2).

Additional specimen examined.

China • Yunnan Province, Diqing, Weixi County, Weiden Town, Fuchuan Village , 27 ° 06 ′ N, 99 ° 10 ′ E, altitude 2900 m, on the fallen branch of angiosperm, leg. C. L. Zhao, 12 October 2023, CLZhao 34279 ( SWFC) .

Figures

Figure 10. Basidiomata of Alloexidiopsis grandinea in general and detailed views (CLZhao 33798, holotype). Scale bars: 1 cm (A); 1 mm (B).

Figure 11. Sections of hymenium of Alloexidiopsis grandinea (holotype, CLZhao 33798) A basidiospores B basidia C cystidia D hyphidia. Scale bars: 10 µm (A); 20 µm (B – D); 10 × 100 Oil.

Figure 12. Microscopic structures of Alloexidiopsis grandinea (holotype, CLZhao 33798) A basidiospores B basidia C basidioles D cystidia E hyphidia F part of the vertical section of hymenium. Scale bars: 10 µm (A – F).