Identification

This mushroom occurs across the United states but is most common west of the Mississippi River. It is found in the summer and fall in deciduous woods, parks, lawns, and gardens. It grows on the ground, singly or in clusters. It is saprobic, obtaining its nutrients from decaying wood. The fruiting body at first is whitish to yellowish, egg-shaped, 1½″ to 2⅜″ tall, and 1¼″ to 2″ wide. It resembles a puffball at least partially submerged in the ground. It is attached to the ground or other substrate by thread-like, branching, similarly colored strands (mycelium). Inside the “egg” there is a gelatinous layer, an olive-green spore mass (gleba), and all of the fully-formed parts of the mature stinkhorn. When conditions are right the “egg” ruptures and expands rapidly. In one or two days it produces a distinctly phallic structure with a stalk and thimble-like head. The rapid expansion is possible because all of the parts are fully formed and compressed inside the “egg”, and because the individual cells elongate, rather than new cells being produced. As the stinkhorn expands the gelatinous layer mixes with the spore mass producing a shiny, putrid slime that covers the cap. The foul-smelling slime is irresistible to flies, which feed on it, lay their eggs in it, and transfer spores when they fly to other stinkhorns. It is a smelly nuisance to homeowners who find the mushroom under their wood deck. The stalk is white to yellowish-white, spike-like, hollow, spongy, fragile, 4″ to 11¾″ tall, and 1½″ to 2″ in diameter. At the base of the stalk the remnants of the ruptured “egg” (volva) is white. The cap is thimble-like, ¾″ to 1½″ in height, and ⅝″ to 1½″ in diameter. There is a white, circular opening at the top where it attaches to the stalk. There are sometimes remnants of a membranous veil attached to the bottom of the cap. At first, the cap is covered with a thick, slimy or gluey, shiny, olive-green to olive-brown, spore-bearing mass (gleba). The gleba has a strong, putrid odor, repulsive to humans but irresistible to flies. When it is carried off by flies and/or washed off by rain it reveals a whitish, pitted and ridged (reticulate) surface. There are no gills.