A black, rubbery jelly fungus that grows on dead attached branches of hardwoods, especially oak. Individual fruitbodies are top-shaped to button-shaped, with a shiny, finely warted upper surface, and they remain discrete rather than fusing. In North America the name has long been applied to black jelly fungi that may include the very similar Exidia nigricans.
Saprobic wood-rotter on dead attached branches and recently fallen wood of broadleaf trees, especially oak, occasionally hazel or beech; in California also on hardwoods and occasionally Monterey pine. Fruits mainly in autumn and winter, or whenever wet.
Distribution
Common in Europe. Its range elsewhere is uncertain because it has been confused with Exidia nigricans (warlock's butter); California Fungi notes that both are known from North America and that the identity of the California species needs more study.
Characteristics
Fruitbody: about 1-3 cm across, top- to button-shaped or irregular, attached at a point; dark sepia to black, gelatinous-rubbery; upper surface shiny with small pimples or warts. Dries to a thin black crust and revives when wet. Spore print: white. Spores: sausage-shaped (allantoid), about 14-19 x 4.5-5.5 um (Wikipedia) or 10-15 x 4-5 um in California material (California Fungi).
