Dense ... clusters of infected annual shoots, tending to be orthotropic ... Leaves thin, soft, dark purple, eventually hymenium-clad beneath between the nerves, hymenium not continuous, individual fascicles distinctly visible. The upper epidermis of the leaf not invaded by the fungus ...

- Nannfeldt, J.A.: (1981) Exobasidium, a taxonomic reassessment applied to the European species^©