Some critical Hyphomycetes. Notes and descriptions

Abstract

The present paper contains descriptions, illustrations, and discussions of the systematic position of certain Hyphomycetes which share the character of producing felted or velvety patches on the lower leaf surface of various Phanerogams, due to the abundant development of the conidiophores and sometimes also of the superficial mycelium. The corresponding indefinite yellowish areas on the upper side of the leaf blade are transformed into necrotic lesions usally only a considerable time after the initial symptoms appear. Four groups have been established within the assembly described.