Witches' butter

Description:

Exidia nigricans forms dark sepia to blackish, rubbery-gelatinous fruit bodies that are button-shaped and around 2 cm (0.79 in) across. The fruitbodies occur in clusters and quickly coalesce to form effused, irregular masses 10 cm (3.9 in) or more across. The upper, spore-bearing surface is shiny and dotted with small pimples or pegs. The individual fruitbodies are each attached to the wood at the base. The spore print is white.

Habitat:

Exidia nigricans is a wood-rotting species, typically found on dead attached branches of a wide range of broadleaf trees. It persists for some while on fallen branches and logs. The species typically fruits in autumn and winter. It is widely distributed in the northern hemisphere, including North America and Europe

Notes:

Exidia nigricans and E. glandulosa are frequently confused. The two are similar, but E. glandulosa produces discrete, top-shaped fruitbodies that rarely if ever coalesce. They are indistinguishable microscopically, but DNA research indicates they are distinct. Tremella foliacea is usually a warmer, lighter brown, but can sometimes be dark sepia to black. Its fruitbodies are gelatinous, but usually foliaceous (with flattish lobes or fronds) and never have warts or pegs on the surface. It is common and occurs on both broadleaf trees and conifers