Family ZANNICHELLIACEAE
Synonyms: Zannichelliaceae APNI*
Description: Aquatic perennial or annual herbs, often rhizomatous. Stems erect, floating or creeping, often producing turions (propagules in the form of buds).
Leaves submerged and/or floating with a distinct midrib, alternate, those subtending inflorescences often subopposite, simple, stem clasping, sessile or petiolate; margins entire or crisped; apex obtuse to acute. Stipules adnate to blade or free.
Inflorescence erect, usually emergent, a pedunculate spike, capitulate to cylindric, with 2–many flowers. Peduncle often bent when fruiting, submerging the fruit. Flowers actinomophic, tetramerous, bisexual. Perianth segments 4, free. Stamens usually 4, epipetalous; filaments adnate to perianth segments; anthers bilocular, extrose, dehiscing by longitudinal slits. Ovary superior; carpels 2–4, free.
Fruit usually interpreted as drupelet, rarely as nutlet or berry. Embryo coiled inside fruit.
Distribution and occurrence: World: 4-5 genera, c. 100 species, cosmopolitan. Australia: 4 genera, c. 18 species, all States.
External links:
Angiosperm Phylogeny Website (Family: Potamogetonaceae, Order: Alismatales)
Wikipedia The description above (from FoA) may need revision to reflect the current taxon concept.
Text by S.W.L. Jacobs, M.A. Brock. Ruppiaceae, in (ed.), Flora of Australia. Australian Biological Resources Study, Department of Climate Change, Energy, the Environment and Water: Canberra. https://profiles.ala.org.au/opus/foa/profile/Ruppiaceae [Date Accessed: 20 March 2025]; page updated by H. Sauquet (Mar 2025)
Taxon concept: APG IV (2016); Jacobs & Brock in Flora of Australia (accessed 2025); Plants of the World Online (2025)
| | Key to the genera | |
| 1 | Ligule longer than the sheath; leaves usually opposite; female flower with cup-like perianth | Zannichellia |
| Ligule shorter than the sheath; leaves mostly alternate but leaves subtending flowers may be opposite; female flowers with 3 distinct perianth segments | Lepilaena |
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