Flaviporus albus Q. L. Wei & H. F. Zheng & F. C. Huang & B. Liu 2023, sp. nov.

Flaviporus albus Q.L. Wei & H.F. Zheng & F.C. Huang & B. Liu sp. nov. (Fig. 2.)

MycoBank:—MB849629

Etymology:—“albus” refers to the white pileus of the specimen.

Diagnosis:—Basidiomes resupinate to pileate. Pileus white to cream, with a covering of sparse white tomentum. Context slightly transparent to semi-transparent when fresh. Hyphal system pseudo-dimitic. Basidiospores broadly ellipsoid to subglobose, commonly with an oil drop, 2.1–2.6×1.7–2.3 μm.

Ecology and distribution:—Known from Xidaming Mountain Nature Reserve, Chongzuo City, and Guangxi Zhuang Autonomous region.

Specimens examined:— CHINA. Guangxi, Daxin county, Fulong Town, elev. 417 m, 31 May 2021, 107°26'41'' E 22°53'6' N, Zheng H.F. (GXU5765, holotype); elev. 439 m 31 May 2021, 107°26'1'' E 22°53'5'' N, Zheng H.F. (GXU5766).

Description:— Basidiomes annual, resupinate to pileate, sessile, clustered, imbricate, up to 5× 3 cm and 4 mm thick, occasionally with radiating spines, watery, very brittle and waxy when fresh, shrinking and becoming very reduced and hard when dried. Pileus surface semi-transparent, covered with sparse whitish tomentum, white to cream, becoming straw-colored and hard when dried, up to 1 mm thick. Sterile margin distinct, white, thin, up to 0.1 mm wide, covered with dense whitish tomentum. Pore surface white when fresh, turning light yellow when dried. Pores small, 10–14 per mm, dentiform, round to angular, with irregular dissepiments. Tubes concolorous with pore surface, up to 1 mm thick. Context slightly transparent to semi-transparent, fragile when fresh, red brown to dark brown when dried, up to 0.1 mm thick, becoming hard.

Hyphal system pseudo-dimitic; generative hyphae clamped, with thin to very thick walls, commonly clamped in thin-walled hyphae, rarely in thick-walled hyphae. Thin-walled hyphae frequently branched and simple septate, 2.7– 7.5 μm in diam, and thick-walled rarely branched with long aseptate segments resembling skeletal hyphae, hyaline, agglutinated and difficult to observe in dried specimens, 2.2–8.5 μm in diam. Gloeopleurous-like hyphae and inflated thin-walled hyphae observed in the trama. Skeletocystidia present in the trama, CB-, IKI-, fusoid to clavate to bulbous, rather thin-walled to thick-walled, 7.2–14.8 μm diam, spiny to lingulate with dense fine crystals at the apex. The crystals are present when Melzer’s reagent and Cotton Blue are used as mountants, but dissolve in KOH and Congo Red. Hyphal pegs present in the hymenium, cylindrical, composed of thin-walled hyphae, 16.8–51.8×11–23.4 μm. Basidioles ellipsoid to dolioform, thin-walled, 4.9–7.9×4.2–5.7 μm. Basidia short clavate to ellipsoid, dolioform, thin-walled, tetraspored, 6.2–10.0×4.4–5.8 μm. Basidiospores broadly ellipsoid to subglobose, hyaline, thick-walled, commonly with an oil drop, IKI-, CB-, 2.1–2.6×1.7–2.3 μm, L=2.4 μm, W=1.97 μm, Q= (1.04)1.09–1.39(1.47), Qm=1.22(n=60/2).

Habitat:—Growing on rotten wood near a stream.