Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Perithecia: immersed in swollen, conspicuous galls (1 wall: brown throughout centrum: I-, K/I- hamathecium: interascal filaments abundant, branched, anastomosing, 1-1.5 µm thick asci: ±cylindrical, shortly stipitate, 60-70 x 12-15 µm, with monostichously arranged ascospores, (6-)8spored ascospores: dark brown, 1-septate, ellipsoid, with both cells ±equal in shape, usually not constricted at the septum, strongly verruculose, frequently with a distinct gelatinous sheath, 11-13 x 6-8 µm. Host: thallus of Heterodermia erinacea, inducing the formation of galls World and Sonoran distribution: Baja California. Notes: The type of Polycoccum heterodermiae was reported as Polycoccum galligenum Vězda (now a synonym of P. pulvinatum (Eitner) R. Sant.) by Triebel et al. (1991), who already mentioned the smaller size of the ascospores in this material with respect to specimens of P. pulvinatum growing on Physcia. As P. heterodermiae, P. pulvinatum induces the formation of conspicuous galls on the host thallus, but its asci, and especially its ascospores, are much larger, over 14 µm long (e.g. 15-18 x 7-9 µm in specimens on Physcia dubia, and 14-21 x 6-9 µm in samples on Physcia tribacia; slight differences may occur depending on the host species, Navarro-Rosin's in litt.).