Azolla Lam.

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.

  • Azolla caroliniana Willd.
  • Azolla filiculoides Lam.
  • Azolla nilotica Decne. ex Mett.
  • Azolla pinnata R. Br. ssp. africana (Desv.) R.M.K. Saunders & K. Fowler


  • Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature.
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria.
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta.Southern African Botanical Diversity Network Report, 13: 1-222.
  • Schelpe, E.A.C.L.E. (1970) Pteridophyta.Flora Zambesiaca, 0: 1-254.