Definitions for "Nostoc"
A genus of algæ. The plants are composed of moniliform cells imbedded in a gelatinous substance.
found in moist places as rounded jellylike colonies
Nostoc is a genus of fresh water cyanobacteria that forms spherical colonies composed of filaments of moniliform cells in a gelatinous sheath. When on the ground, a Nostoc colony is ordinarily not seen; but after a rain it swells up into a conspicuous jellylike mass, which was once thought to have fallen from the sky, whence the popular names, fallen star and star jelly. It is also called witches' butter.