Nostoc spp. Aka Witches butter, star slime, star jelly, trolls butter, witches jelly, mare's eggs, meadow ears, star rot.
The name Nostoc was originally coined by Paracelsus. In early times it was commonly thought that Nostoc was formed from shooting stars which had fallen to earth, giving rise to common names of star jelly, star rot and star slime, which I love. There's plenty of star slime here in central Texas to find if you're interested in checking it out first hand, I find it all over the place near my home in the fields.
Nostoc is a genus of cyanobacteria that forms colonies of moniliform cells in a gelatinous sheath.
Can be found in a range environments such as damp rock, at the bottom of springs and lakes as well as soil and calcareous outcrops. A greenish black gelatinous blob, Nostoc looks a lot like seaweed when it swells up after a good rain. Has large amounts of vegetable gum which contribute to its rubbery, jelly like texture. When it dries out it shrinks down significantly, turning black or brown and inconspicuous.
Nostoc is a nitrogen fixer and an early stage of soil rebuilding, is found worldwide and is able to withstand extreme weather and drought. It has compounds which absorb ultra violet light making it capable of withstanding extreme UV radiation.
Some species of Nostoc are cultivated and eaten as food for their vitamin C and protein content, and medicinal benefits, primarily in Asian, African and South American countries. It's important to note that cyanobacteria are sometimes known to produce beta-N-methylamino-L-alanine (BMAA), a neurotoxic amino acid, in varying quantities. Typically the benefits are considered to outweigh the risks from clean sources of Nostoc and related BGA. Not enough data has been collected to determine the potentially negative effects of Nostoc in the diet.
Swift as the shooting star, that gilds the night
With rapid transient Blaze, she runs, she flies;
Sudden she stops nor longer can endure
The painful course, but drooping sinks away,
And like that falling Meteor, there she lyes
A jelly cold on earth.
William Somervile, 1740
"Seek a fallen star," said the hermit, "and thou shalt only light on some foul jelly, which, in shooting through the horizon, has assumed for a moment an appearance of splendour."
Sir Walter Scott, The Talisman
Species of Nostoc
The species below is of Nostoc commune. You can clearly see the difference between the wet and dry forms of Nostoc here, the wet being greenish brown and rubbery and the dry being somewhat brittle and black.