Rhytisma acerinum. A. Leaves with young (left) and older blackened (right) stromata in field conditions. B. Habit on leaf. C. Part of stroma with ascomata viewed with a dissecting microscope. D. Part of stroma and ascoma in vertical transverse section. E. Asci, ascospores and paraphyses. F. Part of conidioma in vertical transverse section. G. Detail of conidiomatal upper wall in horizontal section. H. Conidiogenous cells and conidia.
