Vegetative characteristics The Nymphaeaceae are annual or perennial, aquatic,
rhizomatous herbs. The family is further characterized by scattered vascular bundles in the stems, and frequent presence of
latex, usually with distinct, stellate-branched
sclereids projecting into the air canals. Hairs are simple, usually producing
mucilage (slime). Leaves are alternate and spiral, opposite or occasionally whorled, simple,
peltate or nearly so, entire to toothed or dissected, short to long
petiolate, with blade submerged, floating or emergent, with palmate to pinnate venation.
Generative characteristics Flowers are solitary, bisexual, radial, with a long pedicel and usually floating or raised above the surface of the water, with girdling vascular bundles in
receptacle. Some species are
protogynous and primarily cross-pollinated, but because male and female stages overlap during the second day of flowering, and because it is self-compatible, self-fertilization is possible. Female and male parts of the flower are usually active at different times, to facilitate cross-pollination, although this is just one of several reproductive strategies used by these plants. There are 4–12
sepals, which are distinct to
connate,
imbricate, and often petallike. Petals lacking or 8 to numerous, inconspicuous to showy, often intergrading with
stamens. Stamens are 3 to numerous, the innermost sometimes represented by staminodes.
Filaments are distinct, free or
adnate to petaloid staminodes, slender and well differentiated from anthers to
laminar and poorly differentiated from anthers; pollen grains usually monosulcate or lacking apertures.
Carpels are 3 to numerous, distinct or connate. The fruit is an aggregate of nuts, a berry, or an irregularly dehiscent fleshy spongy capsule. Seeds are often arillate, more or less lacking
endosperm. ==Taxonomy==