Hei Mu Er

Auricularia auricula-judae (and the closely related A. polytricha) is a saprotrophic jelly fungus of the Auriculariaceae family, widely distributed across temperate and subtropical forests of Asia, Europe, and the Americas, where it grows on dead or dying broadleaf wood, particularly elder, elm, and various Chinese hardwoods. The fruiting body is gelatinous when fresh and dries to a hard, brittle, dark form that rehydrates readily; individual basidiocarps are cup- to ear-shaped, two to ten centimeters across, with a smooth, finely veined or slightly wrinkled upper hymenial surface that is dark reddish-brown to nearly black, and a slightly paler, finely hairy lower surface (A. polytricha is more densely tomentose). Multiple fruit bodies often cluster together along host wood, attached by a small lateral or off-center point.