Pseudofibroporia citrinella

Pseudofibroporia citrinella Yuan Y. Chen & B.K. Cui 2017, in Chen et al., Mycological Progress, 16, 521-533 (2017).

Etymology: citrinella (Lat.): refers to the lemon-yellow pore surface.

Diagnosis: Basidiomata. Annual, pileate, broadly attached, imbricate, fleshy when fresh, crumbly or chalky and light in weight when dry, pilei flabelliform to dimidiate, projecting up to 8 cm, 12 cm wide and 2 cm thick at base; pileal surface white to lemon yellow when fresh, becoming cream to cinnamon buff upon drying, rough, uneven; margin lemon yellow when juvenile, becoming white with age, acute; pore surface lemon yellow to curry buff when fresh, becoming cinnamon buff to clay buff upon drying; sterile margin cinnamon buff to reddish brown, up to 1 mm wide; pores angular, 3–4 per mm; dissepiments thin, entire; context white to lemon yellow, becoming cream to cinnamon buff upon drying, fleshy, cottony or corky after drying, up to 1.5 cm thick; tubes concolorous with pore surface, crumbly or chalky, up to 5 mm long. Hyphal structure. Hyphal system dimitic in context, monomitic in trama; generative hyphae with clamp connections; skeletal hyphae IKI–, CB–; tissues unchanged in KOH. Context. Generative hyphae frequent, with clamp connections, hyaline, thin- to thick-walled with a wide lumen, rarely branched, 3–7.5 μm in diameter; skeletal hyphae hyaline, thick-walled with a wide or narrow lumen, occasionally branched, interwoven, 2–5 μm in diameter. Tubes. Generative hyphae hyaline, thin-walled, occasionally branched, 2.5–6 μm in diam. Cystidia absent; cystidioles bottle shaped, hyaline, thin-walled, 19–25 × 5–6 μm. Basidia clavate, bearing four sterigmata and a basal clamp connection, 17–20 × 5–6 μm; basidioles dominant, in shape similar to basidia but slightly smaller. Spores. Basidiospores oblong to broadly ellipsoid, hyaline, slightly thick-walled, smooth, usually with a small guttule, IKI–, CB–, (3.8) 4–4.5(4.8) × 2.2–2.8(3) μm, L = 4.14 μm, W = 2.5 μm, Q = 1.65–1.68 (n = 60/2).

Index Fungorum Number: IF816307

Notes: Pseudofibroporia citrinella is characterized by flabelliform to dimidiate basidiomata, white to lemon yellow pileal surface when fresh becoming cream to cinnamon buff upon drying, lemon yellow to curry buff pores, acute margin, a dimitic hyphal system in context and monomitic in trama with clamped generative hyphae, bottle shaped cystidioles, and oblong to broadly ellipsoid, slightly thick-walled basidiospores (4–4.5 × 2.2–2.8 μm).