Nostoc

Nostoc, a genus of plants of the natural order Algæ, sub-order Confervaceæ, found upon moist ground, rocks near streams, &c., and consisting of a somewhat gelatinous hollow tumid frond, filled with simple filaments resembling strings of beads. N. commune is frequent in Britain, springing up suddenly on gravel-walks and pasture-grounds after rain. It is a trembling, gelatinous mass, often called Star Jelly, and vulgarly regarded, owing to the suddenness with which it makes its appearance, as having fallen from the skies, and as possessed of important medicinal virtues. N. edule is employed in China as an article of food.