Fruiting body a plasmodiocarp, usually pendent on a slender stalk, sometimes sessile, simple to branched or anastomosing to form a three-dimensional network and then aethaliate. Capillitium elastic, consisting of numerous colourless tubules with mostly limeless junctions and a small number of lime nodes. Spores dark.

Fruiting body an aethalium, often solitary to closely gregarious, irregularly shaped and sometimes very large, consisting of a mass of interwoven, irregular calcareous tubules surrounded by a sterile cortex. Hypothallus often spongy, consisting of several membranous layers, usually forming a distinct margin around the aethalium, colourless to white and then calcareous. Cortex usually well developed but occasionally absent, fragile, usually strongly calcareous. Columella absent. Capillitium consisting of a system of lime nodes and hyaline, tubular connecting threads, often rather scanty. Spores dark in mass.
The genus Fuligo contains 10 species (Lado 2001), two of which have been recorded from New Zealand.