Lesions circular, white to greyish at the centre, purple-black at the margin. Leaf lesions to 5 mm diam, amphigenous, often discolouring the surrounding leaf red. Stem and fruit lesions to 2 mm diam, raised, depressed at the centre.
Anamorph: Sphaceloma rosarum (Pass.) Jenkins (1932). Conidiomata 50-70 µm diam, amphigenous, formed amidst leaf lesions, acervular, subcuticular, partly erumpent, composed of angular hyaline to brown cells, formed amidst lesions. Conidiophores infrequently formed, 1-3 septate, unbranched, hyaline to pale brown, formed from the upper cells of the conidiomata. Conidiogenous cells 3.5-6 x 3-5.5 µm, terminal, integrated, ampulliform, enteroblastic, polyphialidic with 1-3 loci, indeterminate, hyaline to pale brown. Conidia 6-7.5 x 3-5.5 µm, ellipsoidal, simple, hyaline, smooth.
Teleomorph: stromata 40-160 µm diam, subcuticular, partly erumpent, with an outer layer of thick-walled cells ca 40 µm thick, formed amidst and beyond lesions on stems. Ascomatal locules each containing only one ascus and scattered irregularly at several levels within the stroma. Interascal tissue absent. Asci 18-30 x 12-20 µm, globose to ovoid or ellipsoidal, sessile, thick-walled, 8-spored. Ascospores 10-14 x 5-7 µm, hyaline, 1- to 3-septate, constricted at the primary septum, narrowly ellipsoidal to ovoid.
On living leaves of Rosa spp.
S, E & NW England (Berkshire, Suffolk, West Sussex), N.E. Ireland (Armagh), Isle of Man.