The Collaborative International Dictionary of English v.0.48:

Oscillaria \Os`cil*la"ri*a\, prop. n. [NL., fr. L. oscillare to
   swing.] (Bot.)
   A genus of dark green, or purplish black, filamentous,
   fresh-water algae, the threads of which have an automatic
   swaying or crawling motion. Called also Oscillatoria.
   [1913 Webster]