Fruiting body a stalked or sessile sporangium or a plasmodiocarp. Stalk (when present) short, thick, dark. Hypothallus membranous, irregular to contiguous to a group of fruiting bodies, often not evident. Peridium usually double, the outer layer granular, rarely calcareous, sometimes poorly developed, the inner membranous, closely attached. Capillitium of simple or branched tubular threads, slightly roughened to warted or spiny or minutely annulate, but not bearing spirals. Spores yellow, minutely warted or spiny.
This genus contains about 20 species worldwide. A key to many of the more common and widely distributed of these is provided by Keller & Eliasson (1992). Only five species are known to occur in New Zealand.