Abstract
Arachniotus reticulatus isolated from bat dung, is described. It is characterized by reticulate ascospores and yellow or light brown ascocarps. Several isolates of a 2d sp., Arachniotus trisporus, were investigated. Since this sp. lacks a peridium it must be considered a member of the genus Byssochlamys. Further investigation verified the position taken previously by R. K. Benjamin in placing A. trisporus Hotson in synonymy with B. nivea Westling. The morphological development and other diagnostic characteristics of Arachniotus reticulatus and Byssochlamys nivea are discussed. Both spp. produce ascogenous hyphae and croziers prior to ascus production. The position of the genus Byssochlamys within the family Gymnoascaceae is discussed.