Azolla filiculoides Lam.

AMERICAN WATERFERN; PACIFIC MOSQUITOFERN

**

Within the leaf of Azolla is a cavity housing filaments of the nitrogen-fixing cyanobacterium Anabaena azollae (whose generic-level taxonomy is unclear and sometimes put into the genera Nostoc or Trichormus). The taxonomy of Azolla remains muddied. Material in Florida is probably A. caroliniana s.str. Evrard & Van Hove (2004) identified the type specimen of A. caroliniana as synonymous with A. filiculoides, preferring to recognize two species in the USA as A. cristata and A. filiculoides. DNA studies revealed three taxa in California (Song et al. 2025). These DNA studies used the name A. caroliniana for the species in the eastern USA. Both A. filiculoides and A. caroliniana were reported for Virginia, with additional notes on their identification (Bunch & Hayden 2020).

Native OBL (NWPL)