Leafy brain,Jelly leaf, Brown witch's butter

Tremella foliacea is a species of fungus producing brownish, frondose, gelatinous basidiocarps (fruit bodies). It is widespread, particularly in north temperate regions, and is parasitic on other species of fungi (Stereum spp.), that grow on dead attached and recently fallen branches of broadleaf trees and conifers.
Fruit bodies are gelatinous, pale to dark brown, sometimes purple-brown to almost black, up to 20 cm (8 in) across, and seaweed-like (with branched, undulating fronds). Microscopically, the hyphae are clamped and occur in a dense gelatinous matrix. Haustorial cells arise on the hyphae, producing filaments that attach to and penetrate the hyphae of the host. The basidia are tremelloid (globose to ellipsoid, with oblique to vertical septa), 10 to 19 by 8 to 14 μm, usually unstalked. The basidiospores are mostly ellipsoid, smooth, 6.5 to 10 by 4.5 to 8 μm, and germinate by hyphal tube or by yeast cells.