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The Western Australian Herbarium’s collections management system, WAHerb, and DBCA’s flora taxonomic names application, WACensus, have been set to read-only mode since 1 October 2025. Recent taxonomic changes are not currently being reflected in Florabase, herbarium collections, or the census. The Herbarium team, working with the Biodiversity Information Office, now have the Nomos-hosted WACensus in production, and we will begin to update the flora and fungi for WA within the system soon. The Specify project team continues to test and streamline the new collections management system, and we expect this to be online in October. Please reach out to us if you have any questions or concerns.

The notice period started at 9:45 am on Friday, 12 December 2025 +08:00 and will end at 12:00 pm on Thursday, 1 October 2026 +08:00.

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Elatinaceae Dumort.

Reference
Anal.Fam.Pl. p44, 49 (1829)
Name Status
Current
Image

Scientific Description

Common name. Waterwort Family.

Habit and leaf form. (Sub-) shrubs, or herbs. Annual, or perennial. Hydrophytic and helophytic (mostly tolerant of changing water levels); rooted. Leaves submerged and emergent; opposite (and decussate), or whorled (rarely); petiolate to sessile; simple; epulvinate. Leaf blades entire; linear to ovate, or obovate; pinnately veined; attenuate at the base. Leaves with stipules. Stipules interpetiolar. Leaf blade margins entire, or crenate, or serrate. Leaves without a persistent basal meristem. Stem anatomy. Secondary thickening absent, or developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers solitary (axillary), or aggregated in ‘inflorescences’; in cymes. The terminal inflorescence unit cymose. Inflorescences axillary. Flowers small; regular; 2–5(–6) merous; cyclic; tetracyclic, or pentacyclic. Free hypanthium absent. Perianth with distinct calyx and corolla; 4–10(–12); 2 -whorled; isomerous. Calyx 2–5(–6); 1 -whorled; polysepalous, or gamosepalous; imbricate; regular. Corolla 2–5(–6) (the same number as K); 1 -whorled; polypetalous; imbricate; regular; persistent. Androecium 2–5(–6), or 4–10(–12) (i.e. the same number as or twice C). Androecial members free of the perianth; all equal; free of one another; 2 -whorled, or 1 -whorled (the inner whorl sometimes aborted). Androecium exclusively of fertile stamens. Stamens 2–5(–6), or 4–10(–12); isomerous with the perianth, or diplostemonous; when 1-whorled oppositisepalous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 2–5(–6) carpelled. The pistil 2–5(–6) celled. Carpels isomerous with the perianth. Gynoecium syncarpous; synovarious; superior. Ovary plurilocular; 2–5(–6) locular (but the septa sometimes not reaching the ovary apex). The ‘odd’ carpel (when G3) anterior. Gynoecium stylate. Styles 2–5(–6) (same number as locules); free; apical. Stigmas capitate. Placentation axile. Ovules 15–50 per locule (i.e. ‘many’); horizontal to ascending; with lateral or superior raphe; non-arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules valvular (septifragal). Seeds non-endospermic. Cotyledons 2 (relatively short). Embryo straight to curved. Micropyle zigzag (sometimes), or not zigzag. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found.

Geography, cytology, number of species. World distribution: widespread. X = 6, 9. 40 species.