Description: Submerged or emergent aquatic perennials with linear submerged leaves and petiolate floating leaves; tuberous or rhizomatous.
Leaves all basal, margins entire or crisped.
Inflorescence emergent, simple or branched spatheate spikes; spathes persistent or falling early. Flowers usually zygomorphic, bisexual [or rarely unisexual and then plants dioecious]. Perianth segments 1–6, yellow, greenish yellow, or white. Stamens 6 or more, in whorls of 3; anthers 2-locular, extrorse or latrorse, dehiscing by longitudinal slits. Carpels superior, free [or basally coherent], 3–6, mostly sessile; each carpel with ovary narrowed into a style with an inner stigmatic ridge; ovules 1–8 per ovary.
Individual fruit a follicle; each with 1–several seeds. One species sometimes viviparous.
Distribution and occurrence: World: 1 genus, c. 45 species, mostly Africa & Madagascar. Australia: 1 genus, 12 species (11 species native, 1 species naturalized), all mainland States.
Angiosperm Phylogeny Website (Family: Aponogetonaceae, Order: Alismatales)
Text by S. W. L. Jacobs (1993); edited KL Wilson (June 2010)
Taxa not yet included in identification key