Azolla rubra R.Br.
Plants 1-2.5 cm. long, about ovate to suborbicular, bipinnate, often in extensive masses, green to reddish brown above. Fronds densely imbricate, c. 1·5 mm. long, 2-lobed, the lobes about ovate, obtuse. Larger sporocarps globose, c. 1·5 mm. diam. Massulae of microspores with numerous glochidia; megaspores with 3 floats.
DIST.: N., S., St. In still waters throughout. Also Tasmania, Australia. Perhaps better treated, as by Diels, as a variety of A. filiculoides Lam. Azolla almost always harbours Anabaena.
