Fruiting body a stalked or (less commonly) sessile sporangium. Sporotheca globose or cylindrical. Stalk, when present, calcareous, rigid, thick, tapering upward. Hypothallus membranous, small and discoid to extensive and calcareous. Peridium a single layer, thin, iridescent, tending to be persistent. Columella conical to cylindrical, strongly calcareous. Capillitium limeless, consisting of a network of delicate threads, the tips attached to the peridium. Spores black or dark purple in mass.
Twelve species of Diachea have been described (Lado 2001), but only one of these has been recorded from New Zealand.