Calvatia defodiodis Lloyd (Disciseda defodiodis (Lloyd) Zeller) has been found to be conspecific with Gastrosporium simplex Matt. Previously known only from Europe, G. simplex is reported from western Canada and the United States. Distinctive features are the low warted surface of the spores, distinctive calcium deposits in the exoperidium, a gelatinized endoperidium, and a paracapillitium with clamp connections. Information on its known range in North America, microhabitats in which it grows, and its relationship to other Gasteromycetes is presented.