Fruiting body usually a stalked sporangium, but a sessile sporangium, aethalium, pseudoaethalium, or plasmodiocarp is produced by some species. Stalk, when present, short to relatively long, fibrous or hollow, dark. Hypothallus membranous, discoid or contiguous for a group of fruiting bodies, colourless to dark, often not evident. Peridium fugacious or persistent. Capillitium always present, typically consisting of a network of smooth dark threads, usually free from the peridium but occasionally attached to it, arising from the columella or the base of the fruiting body. Columella usually present and often prominent. Spores usually dark coloured (purple-brown to black) in mass, but occasionally the spores are ferruginous or pinkish brown.
Fifteen genera are recognised in the Stemonitaceae. Five of these (Amaurochaete, Brefeldia, Elaeomyxa, Leptoderma, and Stemonaria) are not known from New Zealand.