Anamorph: Conidia catenulate, hyaline, individual cells 3– 8 × 3 –5μm. Teleomorph: basidiomata inducing the formation of galls that are 0.1–1.3 mm diam., initially regularly convex to subglobose, later constricted at the base, sometimes with a central depression and/or tuberculate when mature, very pale to orangish, occasionally brown, waxy gelatinous when wet; often developing on broken fibrils. Context hyphae thin-walled, 2–3μm diam., clamp connections occasionally present. Haustorial branches frequent, mother cell spherical to subspherical, (2–) 3–4 × 3–4 (–5) μm, haustorial filament ca 1 μm diam., to 5 μm long. Hymenium hyaline, containing numerous probasidia. Probasidial initials clavate, often developing from a basal clamp, which is not observed in mature basidia. Basidia, when mature, 20–46 × 4–8 μm, 2-celled (exceptionally 3-celled), with one transverse septum, the two cells laterally much elongate at maturity, sometimes giving the appearance of two immature independent basidia. Individual basidial cells to 40 μm long, 4–8μm diam. Basidiospores 5–8.5 × 5–9μm, Q = 0.7–1, globose to subglobose, with a distinct apiculus ca 1μm diam.