Diaporthe crataegi (All Fungi)
Description contributed by Graham Kinsey, CABI, based on Wehmeyer (1933).
Anamorph: Phomopsis crataegicola Petr. (1920). Conidiomata 750-1000 µm diam. Conidiophores 16-22 x 1.5 µm. Alpha-conidia 7-12 x 4.5-5 µm.
Teleomorph: Stromata on host surface as small pustulate ruptures of the periderm which expose a minute blackened disc 0.2-0.8 mm diam. containing a few ostioles, entostroma pustulate-effuse or occasionally isolate, dorsal zone dipping between the perithecial clusters. Ascomata 240-800 x 160-480 µm, spherical, flattened or irregular from crowding, clustered in the differentiated pustulate areas, collectively erumpent, ostioles cylindrical. Asci 67-95 x 10-12 µm, clavate, with a refractive apical ring. Ascospores 15-18 x 4.5-5.5 µm, cylindric-ellipsoidal, somewhat curved when young, possibly with a gelatinous sheath.
On dead branches of Crataegus.
From England (Cornwall, West Kent, West Norfolk, Surrey, Warks).