Family ALISMATACEAE
Synonyms: Limnocharitaceae APNI*
Description: Emergent aquatics, annuals or perennials, usually with corms, stolons, tubers and rhizomes sometimes tufted (Butomopsis, not in N.S.W.).
Juvenile leaves usually submerged, linear, usually not differentiated into petiole and blade; mature leaves usually with blade expanded, sometimes sagittate; margin entire; petiole with sheathing base.
Inflorescence usually paniculate or umbel-like, sometimes flowers solitary. Flowers actinomorphic, 3-merous, bisexual or unisexual. Perianth in 2 whorls; outer segments 3, sepaloid; inner segments 3, petaloid, falling early. Stamens 3, 6, 9, 12 or numerous; staminodes sometimes present. Carpels superior, free or joined at base, 3–numerous, whorled or apparently spirally arranged; ovules 1–several per carpel, attached basally or to inner angle of carpel.
Fruit an aggregate of indehiscent achenes, dehiscent or indehiscent follicles or thin-walled nutlets. Seeds 1–numerous.
Distribution and occurrence: World: c. 18 genera, 114 species, cosmopolitan. Australia: 8 genera, 12 species, all States.
External links:
Angiosperm Phylogeny Website (Family: Alismataceae, Order: Alismatales)
Wikipedia Hydrocleys and Butomopsis (not in N.S.W) were formerly placed in Limnocharitaceae. Limnocharitaceae is now included in Alismataceae.
Text by Kerry Gibbons, 1 May 2023. Adapted from S.W.L. Jacobs & K.A. McColl, Alismataceae and Limnocharitaceae, Flora of Australia Vol 39 (2011).
Taxon concept: APG IV. Distribution and occurrence: Kew Plants of the World Online; Australian Plant Census [both accessed 21 Apr. 2023].
| | Key to the genera | |
| 1 | Petals usually white or pink; fruits usually achenes, occasionally follicles (Damasonium | 2 |
| Petals usually yellow, sometimes white (not in N.S.W.); fruits follicles | Hydrocleys |
| 2 | Carpels in several whorls, apparently spirally arranged; flowers unisexual, lower flowers female or bisexual, upper flowers male | Sagittaria |
| Carpels in 1 whorl; flowers bisexual
Back to 1 | 3 |
| 3 | Carpels roughly triangular with a long beak, united along central axis | Damasonium |
| Carpels rounded on the back, not triangular, not united along central axis, often closely packed
Back to 2 | Alisma |
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