Gloeocystidiellum cremeum L. Wang & C. L. Zhao, 2025

Wang, Lu, Zhu, Yonggao, He, Siyuan, Jabeen, Sana & Zhao, Changlin, 2025, Additions to the coriaceous families Peniophoraceae and Stereaceae (Russulales): Six novel wood-inhabiting taxa in the genera Conferticium, Gloeocystidiellum, and Peniophora from southwest China, MycoKeys 115, pp. 273-308 : 273-308

Gloeocystidiellum cremeum L. Wang & C. L. Zhao sp. nov.

Figs 7 , 8

Holotype.

China. • Yunnan Province: Zhaotong, Wumengshan National Nature Reserve , GPS coordinates: 27°77'N, 104°25'E, altitude: 1900 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 20 Sep 2023, CLZhao 33623, GenBank: ITS = PQ 287847, nLSU = PQ 295864 ( SWFC!).

Diagnosis.

It is characterized by cream membranaceous basidiomata, a monomitic hyphal system with clamped generative hyphae, thick-walled, subcylindrical to obclavate gloeocystidia, and ellipsoid to subglobose basidiospores.

Etymology.

Cremeum (Lat.): refers to the species having a cream color of the hymenial surface.

Description.

Basidiomata. Annual, resupinate, closely adnate, membranaceous, without odor or taste when fresh, up to 8.5 cm long, 2 cm wide, and 300 μm thick. Hymenophore smooth, white when fresh, white to cream upon drying. Sterile margin cream, up to 1 mm.

Hyphal system. Monomitic; generative hyphae with clamp connections, colorless, thin-walled, smooth, branched, interwoven, 2–3 µm in diameter, IKI –, CB –; tissues unchanged in KOH.

Hymenium. Gloeocystidia numerous, variable in size and shape, subcylindrical to obclavate, colorless, slightly thick-walled, smooth, mostly 70–77 × 7.5–10.5 µm. Basidia subcylindrical to subclavate, slightly flexuous, with a basal clamp connection and four sterigmata, 19–24 × 3–4.5 µm; basidioles numerous, in shape similar to basidia but smaller.

Spores. Basidiospores ellipsoid to subglobose, colorless, thin-walled, smooth, IKI +, CB –, (3.5 –) 4–5 × (2 –) 2.5–3.5 µm, L = 4.41 µm, W = 2.97 µm, Q = 1.39–1.51 (n = 90 / 3).

Additional specimens examined (paratypes).

China. • Yunnan Province: Zhaotong, Weixin County, Tianxing National Forest Park , GPS coordinates: 28°05'N, 105°09'E, altitude: 900 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 5 Jul 2023, CLZhao 29477, GenBank: ITS = PQ 287846, nLSU = PQ 295863 ; • Zhaotong, Wumengshan National Nature Reserve , GPS coordinates: 27°77'N, 104°25'E, altitude: 1900 m asl., on the fallen angiosperm branch, leg. C. L. Zhao, 20 Sep 2023, CLZhao 33690, GenBank: ITS = PQ 287848 ( SWFC!) .

Figures

Figure 7. Basidiomata of Gloeocystidiellum cremeum (holotype CLZhao 33623). Scale bars: 1 cm (A); 1 mm (B).

Figure 8. Microscopic structures of Gloeocystidiellum cremeum (holotype CLZhao 33623): basidiospores (A); basidia and basidioles (B); gloeocystidia (C); a section of the hymenium (D). Scale bars: 5 µm (A, B); 10 µm (C, D).