Description: Perennials with erect basal stems from a shortened stem or corm.
Leaves emergent on long petioles.
Inflorescence on a leafless peduncle, paniculate, with whorls of 3 or more branches subtended by bracts. Flowers bisexual. Sepals 3, green. Petals 3, white to dark pink. Stamens 6. Carpels numerous, free, laterally flattened; style lateral.
Fruit a nutlet. Aggregate fruit a head of 1-seeded nutlets.
Distribution and occurrence: World: 9 species, cosmopolitan but mainly Northern Hemisphere. Australia: 2 species (1 species endemic, 1 species naturalized), N.S.W, Vic., S.A.
Text by S. W. L. Jacobs
Taxon concept:
| | Key to the species | |
| 1 | Leaves with lamina lanceolate, narrowing gradually into the petiole; petals acute; style curved in lower part | Alisma lanceolatum |
| Leaves with lamina rounded to cordate at the base; petals obtuse; style more or less straight | Alisma plantago-aquatica |
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