Differs from other Haploporus species by the combination of a resupinate habit, a dimitic hyphal structure with dextrinoid skeletal hyphae, distinct small pores, 7–9 per mm, the presence of dendrohyphidia, and distinct small ellipsoid basidiospores measuring 5.3–6.7 × 3–4.1 µm.

CHINA. Hainan Prov., Ledong County, Jianfengling Nat. Res., on dead angiosperm tree, 23 March 2011, Dai 12147 (Holotype in BJFC).

Microsporus (Lat.): referring to the small basidiospores of this species.

Basidiocarps annual, resupinate, adnate, soft corky when fresh, become corky upon drying, odor- or tasteless when fresh, up to 20 cm long, 4.5 cm wide and 2 mm thick at center. Pore surface pinkish buff to clay-buff when dry; sterile margin indistinct, very narrow to almost lacking; pores angular, 7–9 per mm; dissepiments thick, entire. Subiculum cream, corky, thin, about 0.2 mm thick. Tubes light buff, corky, about 1.8 mm long.

Hyphal system dimitic: generative hyphae bearing clamp connections, hyaline, thin-walled; skeletal hyphae dominant, thick-walled, frequently branched, dextrinoid, CB–, skeletal hyphae swollen in KOH.

Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.5–2.5 µm in diam; skeletal hyphae dominant, hyaline, thick-walled with a narrow to wide lumen, frequently branched, interwoven, 1.5–3 µm in diam.

Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.5–3 µm in diam; skeletal hyphae distinctly thick-walled with a narrow lumen to subsolid, frequently branched, interwoven, 1–2 µm in diam. Cystidioles present, fusiform, 10–20 × 3.5–6 µm. Basidia barrel-shaped with 4-sterigmata and a basal clamp connection, 11–16 × 5.5–6.5 µm; basidioles dominant, similar in shape to basidia, but slightly smaller. Dendrohyphidia abundant, frequently branched. Some irregular-shaped crystals present among tube tramal structures

Basidiospores ellipsoid, hyaline, thick-walled, with tuberculate ornamentation, dextrinoid, CB+, 5.3–6.7(–7) × (2.9–)3–4.1 µm, L = 5.98 µm, W = 3.90 µm, Q = 1.78 (n = 30/1).