genus of true slime molds (class Myxomycetes; q.v.) whose large fruiting body (compound sporangia), 5 centimetres (2 inches) or more long and about half as wide, occur commonly on decaying wood. The sporangia, on bursting, release fine black spores. Fuligo septica, the best-known species, is also called “flowers of tan,” from the frequent appearance of its yellow fruiting body in tan bark bits used for tanning hides.