Description contributed by Graham Kinsey (CABI).
Host surface not blackened at first, later blackened over wide areas, no ventral zones present.
Anamorph: Phomopsis subordinaria (Desm.) Traverso (1906). Conidiomata 500 x 240 x 150 µm. Conidiophores 15 x 1.5 µm. Alpha-conidia 7-10 x 2-2.5 µm, cylindrical, beta-conidia 15-25 x 1-2 µm.
Teleomorph: Ascomata scattered singly in the host pith, ostioles short-cylindric or slightly elongated. Ascospores 12-15 x 2.5-3.5 µm.
Wehmeyer considered this to belong within the D. arctii aggregate. The only other species on the same host is the extralimital D. plataginis Tassi (1900) which was not seen by Wehmeyer.