Aquatic, caulescent, rhizomatous, laticiferous, mucilaginous herbs, usually stoloniferous with air-canals and scattered vascular bundles devoid of cambium; rhizomes
sympodial, erect; roots adventitious in groups at the base of rhizomes and nodes of
stolons. Leaves alternate, simple, exstipulate, usually long-petiolate, heterophyllous,
submerged and floating, spirally arranged on rhizome, on one side of stolons and
distichous or tristichous, or even opposite or ternate on floating shoots; foliar sclereids
absent. Flowers small, solitary at nodes on floating shoots, usually long-pedunculate,
bisexual, hypogynous, trimerous, with floral appendages arranged in low spirals. Sepals
(2-) 3 (-4), free or slightly connate at base. Petals (2-) 3 (-4), free or slightly connate at
base. Stamens 3 - 36, free, more or less flattened with paired microsporangia arranged
laterally or abaxially, dehiscing longitudinally; pollen uniaperturate; staminodes absent.
Carpels (1-) 2 - 18, free; ovules 1 - 4 in each carpel, anatropous or orthotropous, bitegmic,
crassinuccllate; placentation laminar to submarginal. Fruits ripening under water, indehiscent, 1 -
4-seeded follicles. Seeds exarillate, operculate, with minute embryo, scanty
endopserm and copious perisperm.
Tropical and temperate regions of the world, except Europe; 2 genera and 8 species, 2 genera and 2 species (one introduced) in India.
Notes. Cabombaccae and Nymphaeaccae have much in common with monocots (Dahlgren, 1983).
Literature. DAHLGREN, R. (1983) General aspects of angiosperm evolution and macrosystematics. Nord. J. Bot. 3: 119 - 149. MITRA, R. L. (1990) Cabombaceae. In: Fasc. Fl. India 20: 3 - 7. OSBORN, J. M, T.N. TAYLOR & E.L. SCHNEIDER (1991) Pollen morphology and ultrastructure of the Cabombaceae: correlations with pollination biology. Amer. J. Bot. 78: 1367 - 1378.
Tropical and temperate regions of the world, except Europe; 2 genera and 8 species, 2 genera and 2 species (one introduced) in India.
Notes. Cabombaccae and Nymphaeaccae have much in common with monocots (Dahlgren, 1983).
Literature. DAHLGREN, R. (1983) General aspects of angiosperm evolution and macrosystematics. Nord. J. Bot. 3: 119 - 149. MITRA, R. L. (1990) Cabombaceae. In: Fasc. Fl. India 20: 3 - 7. OSBORN, J. M, T.N. TAYLOR & E.L. SCHNEIDER (1991) Pollen morphology and ultrastructure of the Cabombaceae: correlations with pollination biology. Amer. J. Bot. 78: 1367 - 1378.
KEY TO THE GENERA
| 1a Adult leaves monomorphic, floating, entire; stamens 12 - 18 | 1. Brasenia |
| b. Adult leaves dimorphic, submerged and floating submerged leaves deeply and finely palmately dissected stamens 3 - 6 | 2. Cabomba |
