Description: Small perennial herbs, mat-forming to upright, terrestrial, subaquatic or aquatic.
Leaves opposite, subsessile; stipules interpetiolar, joining bases of opposite leaves; lamina linear (Polypremum) to broadly ovate (Tetrachondra).
Flowers mostly solitary or in leafy cymes, actinomorphic, calyx, corolla and stamens 4-merous, with calyx and corolla connate at base. Calyx campanulate, persistent; lobes narrowly ovate, with apex more or less obtuse. Corolla white, tube subrotate to campanulate. Stamens alternate with corolla lobes, inserted on corolla; anthers antrorse, dorsifixed. Gynoecium consisting of 2 joined carpels; ovary semi-inferior (Polypremum) and style terminal or superior (Tetrachondra) and style gynobasic; stigma slightly truncate to capitate.
Fruit a 2-valved capsule or reduced to 4 separate mericarps.
Distribution and occurrence: Introduced to North Coast (N.S.W.) and Queensland. Natural to SE U.S.A., S. America and New Zealand.
Angiosperm Phylogeny Website (Family: Tetrachondraceae, Order: Lamiales)
Text by B.J. Conn (2006)
Taxon concept: B.J. Conn (2006)
|One genus in NSW: Polypremum|