THE ORIGIN AND AFFINITIES OF THE CERATOPHYLLACEAE

Summary Historically, the phylogenetic affinities of the Ceratophyllaceae have been vague, however, recent authors have favored a close relationship of the family to the genus Cabomba of the Nymphaeales. An evaluation of critical character distributions by cluster analyses confirmed relationships of Cabomba with Brasenia, Euryale with Victoria , and Nymphaea with Nuphar, Ondinea , and Barclaya , but did not support a close affinity of Ceratophyllum to any nymphaealean genus. By phenetic analyses, Ceratophyllum is distinct and not recognizable as a natural component of the Nymphaeales. This conclusion is in line with revised interpretations of available data from various sources, which point to an isolated position of the Ceratophyllaceae. Paleobotanical evidence supports a hypothesis that the Ceratophyllaceae are a vestige of ancient angiosperms that diverged early from the line leading to most other modern taxa. The remoteness of Ceratophyllaceae from the Nymphaeales and other extant angiosperms warrants the recognition of a new, distinct order of flowering plants.