Description contributed by Graham Kinsey, CABI, based on Wehmeyer (1933).
Anamorph: Phomopsis convallariae (Westend.) Grove (1921). Conidiomata 1000 x 400 x 300 µm. Conidiogenous cells 12-18 x 1.5 µm. Alpha-conidia 7-9 x 1.5-2.5 µm.
Teleomorph: stromata appearing on the surface as sharply outlined entostromatic areas which are elongated and elliptic to oblong, confluent or more widely effuse, surface blackened or not. Ascomata 320-480 x 120-160 µm, spherical or somewhat flattened, scattered singly or occasionally in small groups of 2-3, ostioles short-cylindrical to conical and slightly erumpent. Asci 40-55 x 6-8 µm, clavate. Ascospores 9.5-12(-15) x 2.5-3.5(-4) µm, fusiform-ellipsoidal, slightly constricted at the septum.