The fossil record of the Nymphaeales is primarily in the form of seeds, though pollen, stems, leaves, and even flowers have been found. The oldest of these fossils are from the Cenomanian in the Late Cretaceous; later Maestrichtian fossils include Zonosulcites (the oldest pollen) and Barclayopsis from Europe (the oldest waterlily seeds). Also from the Cretaceous have come reports of leaves resembling those of Brasenia and Nelumbo, though pollen of the latter genus is unknown prior to the Eocene. The abundance of fossil seeds from this group has led some to suggest that the waterlilies were more diverse in the past than they are today (Cevallos-Ferriz & Stockey 1989).
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Miocene Waterlilies : At left are a fossilized rhizome and leaf of Nymphaea diatoma from the Miocene of Oregon. At right is the fossilized rhizome with roots of Nymphaeites nevadensis from Buffalo Canyon, Nevada.
Sources:
S. R. S. Cevallos-Ferriz & R. A. Stockey. 1989. Permineralized fruits and seeds
from the Princeton chert (Middle Eocene) of British Columbia: Nymphaeaceae. Botanical Gazette 150(2):207-217.
M. E. Collinson. 1980. Recent and Tertiary seeds of the Nymphaeaceae sensu lato with a revision of Brasenia ovula (Brong.) Reid and Chandler. Annals of Botany 46:603-632.
L. J. Hickey & J. A. Doyle. 1977. Early Cretaceous fossil evidence for angiosperm evolution. Botanical Review 43(1):3-104.
J. Muller. 1981. Fossil pollen records of extant angiosperms. Botanical Review 47(1):1-142.
