Fruiting body a short-stalked or (more commonly) sessile sporangium or sometimes plasmodiocarpous. Hypothallus usually inconspicuous. Peridium membranous to cartilaginous. Columella absent. Capillitium present and consisting of smooth or obscurely sculptured, simple or forked, slender threads, attached to the base of the fruiting body and to the peridium. Spores pallid or yellow, sometimes pinkish at first, free or united in clusters.
Seven species of Dianema have been described (Lado 2001), and three of these have been collected in New Zealand. All species of Dianema appear to be uncommon, and members of the genus do not seem to occur in the tropics (Farr 1976).