GNU Webster's 1913 - n. (Bot.) A genus of algæ. The plants are
composed of moniliform cells imbedded in a gelatinous substance.
“A compound isolated from a cyanobacterium, a type of blue-green
algae known as Nostoc, shows promise ...” “Nitrogen fixation and
photosynthesis in high arctic forms of Nostoc commune.” “Two
alga-like creatures that are actually blue-green bacteria
sometimes figure in the kitchen: the nutritional supplement
spirulina and the Chinese “hair vegetable” or “hair moss,”
species of Nostoc, which grows in mountain springs in the
Mongolian desert.” “Colonies of _Nostoc_ are constantly found
living in some of the mucilage slits which then become
enlarged.” “_Nostoc_ are constantly found in the Anthocerotaceae
and in _Blasia_.” “The ventral surface bears flat scales in
addition to the concave scales which, as mentioned above, are
inhabited by _Nostoc_.” “_Collema_ (Fig. 44, _C_, _D_, _E_), a
dark greenish, gelatinous form, growing on mossy tree trunks,
and looking like a colony of _Nostoc_, wh