Synonyms: Lepilaena APNI*
Description: Submerged dioecious or monoecious aquatic annuals or short-lived perennials with slender rhizomes; often much branched and, in flowing water, may be to 1 m long or, under unfavourable conditions, c. 0.5 cm high.
Leaves alternate or ± opposite when subtending flowers, 1-veined, usually <1 mm wide, with a basal auriculate or ligulate sheath.
Flowers usually unisexual, axillary, solitary but often clustered. Male flower with a reduced perianth of 3 scales or cup-like and a single anther mass either 4- or 12-sporangiate. Female flowers with 3 membranous perianth segments; carpels 3, free; stigma oblique, cylindrical or funnel-shaped.
Distribution and occurrence: World: 9 species, Australia, New Zealand & southern Pacific islands, Mediterranean to Central Asia, South Africa. Australia: 7 species (native), all States except N.T.
Formerly separated in Australia as the genus Lepilaena . Previously placed in the segregate family Zannichelliaceae.
Text by S. W. L. Jacobs; updated by R. L. Barrett (June 2019)
Taxon concept:
| | Key to the species | |
| 1 | Stigmas deeply divided (laciniate); male flower with a single 4-sporangiate anther; leaves with apex more or less truncate, sometimes mucronate | Althenia bilocularis |
| Stigmas entire; male flower with a 12-sporangiate anther mass; leaves with apex acute to obtuse2 | |
| 2 | Leaves gradually tapering towards apex, apex margins minutely serrate; style much shorter than fruiting ovary; fruiting carpels strongly keeled, bluntly tuberculate when dry; perianth segments of female flower entire | Althenia australis |
| Leaves abruptly tapered at apex, apex margins entire; style c. as long as fruiting ovary, very slender; fruiting carpels smooth; perianth segments of female flower bifid
Back to | Althenia preissii |
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