The genus Physalacria was established by Peck in 1882 when he showed that the fungus described by Fries as Mitrula inflata and later by Cooke as Spathularia inflata was actually a Basidiomycete (6). In an excellent description, Peck stated that the surface of the bladder-like head is everywhere covered by the hymenium; and on this basis he included the genus in the family Clavariaceae, where it is generally placed at the present time. He also mentioned that he could find but two sterigmata on the basidia. Krieger (3), examining fresh specimens, claims to have found several characters at variance with Peck's description. He asserts that the cap is differentiated into distinct upper and lower surfaces, and that the hymenium is borne only on the latter. The upper surface, he finds, shows a looser cell arrangement, with hair-like and encrusted cells scattered about the transition from hymenial to sterile surface. Moreover, the hymenial surface is described as typically thrown into gill-like folds, each ending at the stipe in a decurrent tooth, much as do decurrent gills. The specimens studied by Krieger apparently all grew erect and the hymenium was in the same relative position as it is in a stalked agaric. Because of this restriction of the hymenium to the lower surface and the resemblance of the folds on the lower surface to gills, Krieger proposed to remove the fungus from the Clavariaceae to the Agaricaceae, renaming it Eoagaricus inflatus. He states (3, 4) that the stipe is always laterally attached, so that the radiately folded, gill-like hymenium, borne on one side of the stipe, faces downward in the young basidiocarp. As maturity is reached the bladder-like cap is erected by contraction of the tissues of the stipe on one side. The figure illustrating this (4, p. 192) is contradictory, however, in that the folds shown are not radiate and do not appear to terminate at the stipe in decurrent teeth.