The Collaborative International Dictionary of English v.0.48:
Azolla \Azolla\ n. a genus of ferns, someties placed in its own family Azollaceae. Syn: genus Azolla. [WordNet 1.5]WordNet (r) 3.0 (2006):
Azolla n 1: a genus of fern sometimes placed in its own family Azollaceae [syn: Azolla, genus Azolla]