Nymphaeales are predominantly
Members Nymphaeales dominate freshwater aquatic ecosystems worldwide temperate tropical: rhizomatous rooted hydrophyte with floating peltate orbicular leaves possessing extensive aerenchyma lacunae, hydropoten absorbing trichomes, epistomatic stomata only upper surface, long petioles with air canals, insect-pollinated showy flowers with spiral perianth emerging above water beetle pollinated. Species like Nuphar lutea yellow water lily, Nymphaea alba white and giant Victoria amazonica exhibit adaptive modifications for aquatic life such as heterophylly submerged filamentous leaves. Terrestrial shrubs, epiphytic growth or desert succulence xerophytic absent. Order exemplifies early angiosperm ecological diversification into aquatic niches before terrestrial dominance and high diversity.
Ref: NCBI Taxonomy and Campbell Biology, Chapter 30: Nymphaeales aquatic water lily habit