What is "witches' butter"

Nostoc \Nos"toc\, prop. n. [F.] (Bot.) A genus of alg[ae]. The plants are composed of moniliform cells imbedded in a gelatinous substance.

Note: Nostoc commune is found on the ground, and is ordinarily not seen; but after a rain it swells up into a conspicuous jellylike mass, which was formerly supposed to have fallen from the sky, whence the popular names, fallen star and star jelly. Also called witches' butter.

n. Any of several gelatinous organisms, such as (taxlink Nostoc commune species noshow=1) and (taxlink Exidia glandulosa species noshow=1).

n. a yellow jelly fungus [syn: Tremella lutescens]

Witches' butter (or Witch's butter) may refer to:

• Exidia nigricans, a black, gelatinous fungus
• Exidia glandulosa, a black, gelatinous fungus
• Tremella mesenterica, a yellow, gelatinous fungus
• Dacrymyces, a jelly fungus often confused with Tremella
• Nostoc, a genus of gelatinous cyanobacteria