A revision of the genera Radiigera and Pyrenogaster

Radiigera was described to accommodate three species of fungi that closely resemble species of the genus Geastrum. Radiigera species are similar to Geastrum species in spore characters and sporocarp macromorphology. The sporocarp in Radiigera differs from that in Geastrum in not dehiscing at maturity and in lacking the endoperidium found in all Geastrum species. Radiigera is a member of the Geastraceae and includes the following species: R bushnellii sp. nov., known only from Oregon; R flexuosa sp. nov., known only from Sweden; R. fuscogleba, known from throughout California, Colorado, Idaho, Oregon, Washington, Utah, and Baja California; and R. taylorii, known from California, New Mexico, Oregon, Washington, and Mexico. Pyrenogaster initially was described to accommodate a species from France that was unusual in the macromorphology of the gleba. Subsequent exploration revealed that P. pityophilus was fairly common in pine forests of southern Oregon. Investigation of Radiigera atrogleba revealed it to be more closely related to P. pityophilus than to any member of Radiigera. A key to both Radiigera and Pyrenogaster and an evaluation of all species previously ascribed to Radiigera is presented.