Description:

• Perennial, freshwater aquatics; rhizome tuberous, densely covered with thin, dead and living roots
• Leaves all basal, in tufts at tip of tuber, submerged, aerial or with a floating blade; juvenile leaves often strap-shaped; adult leaves usually petiolate, with expanded, linear, elliptic or oblong lamina, mostly with a distinct midrib and 1 or more pairs of parallel main veins with many cross connections; stipules 0
• Inflorescence simple or forked, exserted spikes, enveloped in bud by a usually early caducous, hood-shaped spathe
• Flowers bisexual and protandrous, rarely female by suppression of anthers, usually irregular, hypogynous, ebracteate, arranged dorsally or around axis; pollination entomophilous
• Perianth segments 1 or 2, rarely up to 6, or sometimes 0, petal-like or bract-like, free, persistent or deciduous (viz. in Aponogeton stuhlmannii and some closely related species), white, pink, red, mauve or yellow, folded inwards in bud stage, spreading later, turning green with age if persistent
• Stamens 3 + 3, rarely more, then in 3 or 4 circles, free; anthers small, 2-thecous, with thecae facing in opposite directions, basifixed; pollen separate, ellipsoid to globose, sulcate, foveolate
• Gynoecium of 3-6(-9 in apomicts) free, sessile, turbinate carpels, attenuated into a style; style curving outwards and forming a stigmatic ridge on ventral suture; ovules 2-8 per carpel, basal, anatropous
• Fruit of distinct, ± free follicles, membranous, opening on adaxial side; outer skin soon disintegrating; ripening often taking place under water
• Seeds 1-6 per follicle, fusiform, in some species with a soft spongy outer covering
• x = 8, 13 (aneuploids)

Nomenclature:

• Aponogeton L.f.
  • Linnaeus f.: 32 (1782)
  • Obermeyer: 85 (1966)
  • Van Bruggen: 241 (1968)
  • Van Bruggen: 121 (1969)
  • Van Bruggen: 457 (1970)
  • Van Bruggen: 193 (1973)

Distribution & Notes:

• Global: Species 14, Africa
• Southern Africa: Species 7, widespread, frequent in freshwater pools, swamps, flood plains, seasonally inundated grasslands, slow- or fast-flowing water