Fruiting body a stalked (or rarely subsessile) sporangium, usually occurring in clusters. Sporotheca cylindrical, reddish or liliaceous brown to black. Stalk slender, smooth, black, usually shiny. Hypothallus membranous, usually contiguous for a group of sporangia, colourless and shining or silvery to brown. Peridium usually fugacious. Columella a continuation of the stalk, reaching at least to the middle of the sporotheca and often nearly to the apex. Capillitium arising from the entire length of the columella, with the branchlets merging into a surface net that is developed under the peridium. Spores dark brown to purplish brown or black, reddish brown or lilaceous.
Approximately 20 species have been described in the genus Stemonitis (Lado 2001), and nine of these are known from New Zealand.