Ceratopteris Brongn., Bull. Sci. Soc. Philom. Paris 1821: 186

Kessler, Michael, Smith, Alan R. & Prado, Jefferson, 2017, Prodromus of a fern flora for Bolivia. XXVII. Pteridaceae, Phytotaxa 332 (3), pp. 201-250 : 218

Ceratopteris Brongn., Bull. Sci. Soc. Philom. Paris 1821: 186 . 1822.

A pantropical, aquatic genus, either floating or rooted in the mud. Unmistakeable. Perhaps six species, only one in Bolivia. Fronds are dimorphic or subdimorphic, with fertile fronds having more dissected blades and narrower pinnae and pinnules. The genus has a unique chromosome base number in Pteridaceae : x =39. The spores are large, globose, and with a distinctive ornamentation comprising parallel ridges. Hickok & Klekowski (1974) produced evidence for pairing of non-homologous chromosome pairing in C. thalictroides (L.) Brongn., a second widespread species possibly occurring in Bolivia.

Ceratopteris is monophyletic and sister to Acrostichum in all phylogenetic analyses (e.g., Schuettpelz et al. 2007). The species were reviewed by Lloyd (1974).