Vararia isabellina Y.L. Deng & C.L. Zhao, 2024

Deng, Yinglian, Jabeen, Sana & Zhao, Changlin, 2024, Species diversity and taxonomy of Vararia (Russulales, Basidiomycota) with descriptions of six species from Southwestern China, MycoKeys 103, pp. 97-128 : 97

Vararia isabellina Y.L. Deng & C.L. Zhao sp. nov.

Figs 5 , 6

Holotype.

China. Yunnan Province, Lincang, Fengqing County, 24°67'18"N, 100°19'67"E, altitude 1660 m a.s.l., on the fallen angiosperm branch, leg. C.L. Zhao, 20 July 2022, CLZhao 22852 (SWFC).

Etymology.

Isabellina (Lat.): referring to the isabelline to yellowish-brown basidiomata.

Description.

Basidiomata annual, membranous, soft, and adnate, without odor or taste when fresh, up to 90 mm long, 10 mm wide, and 50-90 µm thick. Hymenial surface smooth, cream to isabelline when fresh, isabelline to slightly brown when dry. Sterile margin thinning out, cream to isabelline, and up to 1 mm wide.

Hyphal system dimitic, generative hyphae bearing simple-septa, colorless, thin to slightly thick-walled, frequently branched, 2.5-4 µm in diameter, IKI-, CB-, tissues unchanged in KOH. Dichohyphae predominant, yellowish, distinctly thick-walled, dichotomously to irregularly branched with main branches up to 4 μm in diameter and with acute tips, moderately dextrinoid in Melzer’s reagent, CB-, tissues unchanged in KOH; dichohyphae in hymenium similar to those in subiculum but more branched, with more narrow and shorter branches, with slightly curved tips and stronger.

Gloeocystidia spindle to subcylindrical, smooth, colorless, thin-walled, usually containing refractive materials, 38-47 × 8-13 μm. Basidia subcylindrical, slightly constricted at the neck, with four sterigmata and a basal simple septum connection, 33-39 × 7-9 μm; basidioles dominant, in shape similar to basidia, but slightly smaller.

Basidiospores sub-fusiform to navicular, colorless, smooth, with numerous oil-drops, thin-walled, IKI-, CB-, 9-13 × 5-8 µm, L = 11.66 µm, W = 6.69 µm, Q = 1.68-1.78 (n = 60/2).

Additional specimen examined

(paratype). China. Yunnan Province, Lincang, Fengqing County, 24°67'18"N, 100°19'67"E, altitude 1660 m a.s.l., on the fallen angiosperm branch, leg. C.L. Zhao, 20 July 2022, CLZhao 22887 (SWFC).

Figures

Figure 5. Basidiomata of Vararia isabellina (holotype). Scale bars: 1 cm (A); 1 mm (B).

Figure 6. Microscopic structures of Vararia isabellina (holotype) A basidiospores B basidioles C basidia D dichohyphae E gloeocystidia F a section of hymenium. Scale bars: 10 µm (A-F).