Abstract
A disease of Hibiscus syriacus interested the author, since the causal fungus has been thought to belong to a rarely known, but an important fungal genus. The disease spots appear on the leaves first in summer, but it becomes severe in autumn. The spots are subcircular, at first light brown, discolor to dark brown, then greyish brown. It is caused by a fungus Corynespora Hibisci nov. spec. Since the genus Corynespora was established by GÜSSOW in 1906, it has long included one species only. In some cases even the existence of the genus was doubted. C. Hibisci, the causal fungus of the brown spot disease, is the second species in this genus. Isolation and inoculation of the causal fugnus has been carried out and the pathogenic nature of this fungus has been ascertained. Germ-tubes are sent from the distal or proximal end of the conidia. At the tip of the germ-tubes an appressorium is formed, and an infection hypha is sent, which penetrates the epidermis at the anticlinal wall of the epidermal cells. Soon a necrosis occurs in the host tissues. A detailed comparison of the causal fungus with related fungi and its technical description have been given.
