Alternative names: Not Applicable

Description:
Slender aquatic, amphibious or marsh-inhabiting glabrous herbs; stems floating, or in terrestrial forms prostrate or weakly erect, rooting at the nodes; leaves opposite, entire, widely spaced below, usually clustered at the tip into a flat rosette, in aquatic forms often dimorphic.

Flowers unisexual, both sexes on the same stem, solitary or in pairs in the leaf axils, if paired then usually 1 male and 1 female, each flower subtended by a pair of bracteoles or naked, petals and sepals absent; male flower consisting of a single stamen, with a 2-celled anther on a filiform filament; female flower consisting of a single ovary, 2-celled at first, becoming 4-celled by development of a false septum, with 2 filiform free styles; fruits inconspicuous, usually less than 2 mm broad, approximately circular in outline, flattened, with a shallow longitudinal groove on each face and a deeper commissural groove running around the margin.

Fruit dividing into 4 single-seeded nutlets at maturity, nutlets frequently winged or keeled on the outer edge.

Distribution:  A single cosmopolitan genus, (excluding southern Africa) with about 25 species, 10 of them in Australia. R. Mason (1959), Callitriche in New Zealand and Australia. Aust. J. Bot. 7:295-327; H. I. Aston (1973) Aquatic plants of Australia, pp. 49-60; A. E. Orchard (1980) Callitriche (Callitrichaceae) in South Australia. J. Adelaide Bot. Gard. 2:191-4.

Biology: No text

Author: Prepared by A. E. Orchard