North American species of Coprotus (Thelebolaceae: Pezizales)

The genus Coprotus is a segregate of the coprophilous genus Ascophanus Boud. characterized by minute, translucent, white to yellow apothecia, operculate, non-amyloid, eight- to multi-spored asci, and hyaline, smooth, thin-walled ascospores that contain gas bubbles. Species are distinguished by (1) the number of spores per ascus, (2) the presence or absence of pigments in paraphyses and excipular cells, and (3) the relative size and shape of asci, spores, and sterile elements. Five new combinations are made and six new species are proposed. Keys, descriptions and illustrations are provided for the 18 recognized North American species.