witches' butter

plural witches' butters · alternative witch's butter

1. Any of several gelatinous fungi which are generally yellowish (resembling globs of butter) or black (resembling black butter), including those of the species:
   1. uncountableusuallyTremella mesenterica, a yellow, gelatinous fungus (yellow brain fungus, golden jelly fungus).
   2. uncountableusuallyDacrymyces, a genus of yellow jelly fungus often confused with Tremella.
   3. uncountableusuallyDacrymyces chrysospermus (orange witch's butter).
   4. uncountableusuallyExidia nigricans, a black, gelatinous fungus.
   5. uncountableusuallyExidia glandulosa (black witch's butter).
2. uncountableusuallyThe yellow slime mold Fuligo septica.
3. uncountableusuallyCertain species of Nostoc of blue-green algae, especially Nostoc commune, that form a brownish gelatinous mass when wet.