Lobster mushroom

Lobster mushroom (Hypomyces lactifluorum) is not a true mushroom. It is a parasitic mold that grows on mushrooms, turning them a reddish orange color that resembles the outer shell of a cooked lobster. In particular it colonizes members of the genera Lactarius (Milk-caps) and Russula, such as Russula brevipes and Lactarius piperatus in the western U.S.. At maturity, a lobster mushroom will so thoroughly cover its host that the underlying mushroom may be unidentifiable. Lobster mushrooms can parasitize a variety of mushrooms, some of which might be toxic, but lobsters are widely eaten and enjoyed by experts. They have a seafood-like flavor and a dense, meaty texture, but may taste peppery if an acrid Lactarius is colonized.

A related North American species, Hypomyces luteovirens, has a distinctive yellow-green color, and only partially covers the host fruiting body, often leaving the cap surface untouched. Its range extends primarily through the Pacific northwest, but it has been collected in eastern localities. Unlike H. lactifluorum, this species is not considered a desirable edible.