Monographs Details: Azolla filiculoides Lam.
Authority: Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.
Discussion:Type. Straits of Magellan. Commerson s.n. (P-Lam!).
Differing from both Azolla caroliniana and A. mexicana in plants elongate, frequently 2-6 cm long; from A. caroliniana differing in the larger, papillose, imbricate leaves (1 mm long) and megaspores present; from A. mexicana differing in the nonseptate glochidia, megaspores reticulate on basal portion, and lower lobe of leaf about equal to upper lobe.