Anamorph: conidiogenous cells frequent in old basidiomata, 12-30 x 3-6 µm, clavate to subcylindrical, with a number of short apical branches 1-4(-6) µm in length. Conidia asteroid, 10-14 µm diam., with 4( -5) arms, individual arms 4-6 µm long.
Teleomorph: basidiomata inducing the formation of distinct galls on the host thallus, 2-4 mm diam., often lobate, sometimes tuberculate, frequently with a strongly constricted base, the margin sometimes ciliate. Lower surface of lobes concolourous with the lichen thallus or brownish, upper surface pale brown, reddish brown, rarely orange or dark brown, smooth, shiny, rarely matt or pruinose. Context hyphae 1·5-3 µm diam., clamps not observed. Haustorial branches not observed. Hymenium containing numerous probasidia and conidiogenous cells, intermixed with brown hyphae of the host. Probasidial initials clavate, ellipsoidal or subspherical, clamps not observed, hyphidia and cystidia absent. Basidia 12-23 (-33) x 5-15 µm when mature, ellipsoidal to clavate, often with an attenuated base, with 1-3 longitudinal, oblique or transverse septa. Epibasidia 2-3·5 µm diam., to 40 µm long. Basidiospores 5-8 x 4-7 µm, ellipsoidal, with a distinct apiculus.
Not formally evaluated. In GB&I, only known from a single collection but the species may be under-recorded.
In GB&I, on thalli of Parmotrema reticulatum.
In GB&I, reported only from Ireland (VCH3 West Cork). Otherwise only known from Spain and Portugal in Europe, but with a very wide distribution worldwide over a wide latitudinal range.
Parasitic and gall-forming. Its extensive distribution and relatively wide host range suggests that this might be a complex of cryptic species.