Description contributed by Graham Kinsey, CABI, based on Wehmeyer (1933).
Anamorph: not known.
Teleomorph: stromata variable, on host surface as numerous angular ruptures of the periderm exposing the blackened bark surface or as small groups of pustulate erumpent ostioles, dorsal zone as a heavy blackening of the bark surface over the entire area or locally around the ostioles. Ascomata irregularly and thickly scattered or loosely grouped in the bark or wood, ostioles erumpent singly or in small clusters and usually short-cylindrical or rarely elongate, appressed or sinuous. Ascospores 10-15 x 2.5-4 µm.
Wehmeyer considered this to belong within the D. eres aggregate.
Immature material may be confused with Cryptodiaporthe lebiseyi which also occurs on Acer in GB & I but which lacks any blackened zones and has very small ostioles.
On dead branches of Acer.
From England (including West Gloucs, Herefs, North Lincs, Worcs), Scotland (Shetland) and Wales (Merioneth).