Photo: BT. Wursten
Description of the genus
Free-floating aquatic plants; rhizomes slender, roots simple. Leaves alternate in 2 rows, equally lobed with submerged lobe containing cavities with cyanobacteria and a chlorophyllous floating lobe, veins free. Sori in sporocarps borne in axils of submerged lobes.
Derivation of name: azo: dry, ollyo: to kill; plants are killed by drought
Comment: Some authors place the genus Azolla within the family of the Azollaceae. Recent literature (Roux 2009, Crouch 2011) however include the genus Azolla within the Salviniaceae.
Worldwide: c.6 species in tropical and warm areas, introduced in many ares
We have 4 taxa in the database for Azolla.