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Family: Azollaceae

Kingdom: Plantae Rank: Family Parent: Hydropteridales Status: Valid

Common Names:

  • AZOLLA FAMILY - English, United States of America
  • MOSQUITO FERN FAMILY - English, United States of America
  • WATER FERN FAMILY - English, United States of America

Morphological Description

Family Recognition in the Field: Tiny, moss- or liverwort-like, free-floating or mat-forming plants that sometimes form conspicuous velvet-like, green to red mats on the surface of quiet waters.


Notes: A cosmopolitan family of a single genus and only ca. 7 species (Lumpkin 1993) of floating aquatics (sometimes stranded on mud) with highly reduced vegetative morphology (Saunders & Fowler 1992). Because of their minute size and numerous leaves, the plants superficially resemble mosses or liverworts. The family is often included in the Salviniaceae, but according to Lumpkin (1993), the relationship is not close. Three families of heterosporous water ferns occur in East TX (Azollaceae—Azolla, Marsileaceae—Marsilea, Pilularia, and Salviniaceae—Salvinia). These groups are quite distinct morphologically, and traditionally the marsileaceous (Marsilea and Pilularia) and salviniaceous (Azolla and Salvinia) lines were considered to have evolved independently from different homosporous fern ancestors. However, based on recent morphological, fossil, and molecular evidence, all three living heterosporous water fern families appear to comprise a monophyletic group (Rothwell & Stockey 1994; Hasebe et al. 1995; Pryer 1999).