About this fungus
Witch's Butter is a fungus in the Tremellaceae family. Its habitat and field characteristics are summarised below.
A glossy yellow to orange mass of soft, folded jelly emerging through the bark of a dead broadleaf branch.
What to check
Confirm thin, shiny, brain-like lobes with no cap, stem, gills or pores, on dead broadleaf wood. Search the same branch for the flat crust fungus Peniophora, because Witch's Butter parasitises that fungus rather than the wood itself. Host evidence is more reliable than colour alone.
Variation
Fresh wet fruit bodies are plump, translucent and bright golden yellow to orange. In dry weather they shrink into a hard darker film and swell again after rain. Very pale forms occur rarely.
Lookalikes
Naematelia aurantia can be almost identical but parasitises Stereum, a bracket-like crust with visible projecting edges. Dacrymyces species commonly form smaller pustules on conifer wood. Microscopy or confirmation of the host fungus may be needed for difficult examples.
Habitat and range
Parasitic on Peniophora species living in dead attached or fallen branches of broadleaf trees. It is widespread across northern temperate regions and can appear in any wet season.
Food safety
Inedible.
Photographs
Dan Molter (shroomydan) / CC BY-SA 3.0