Distribution:  Worldwide (cosmopolitan).  4 genera in the Texas flora, each with 6 species.

Floral structure:

Significant features:  Classic archaic floral structure, many parted, solitary with poor differentiation between the calyx and corolla with gradation extending to the androecium.  This combines, however, with specialization for a specific habitat - an aquatic environment.  All species are aquatic, perennial herbs with underwater rhizomes and long-petioled, peltate leaves.  The Nymphaeales is one of the few angiosperm Orders with all taxa adapted to a specific habitat.  Also, all taxa of lack vessel elements.  It is believed that this is a derived condition (ancestors had vessel elements in the xylem) related to the aquatic environment of these plants.  Monocots also tend to lack vessel elements in the xylem.  This, and other linkages, have suggested to Cronquist that "..the premonocotyledonous dicots were probably something like the Nymphaeales."  Thus, of all dicot Orders and Families considered here, this one carries a possible link to the monocots.

Nymphaea - water lily flower at anthesis



Victoria cruziana - flower with leaves - stem (rhizome) under water

More information on the Nymphaeaceae