Greek echinos – hedgehog, doros – bag, referring to the head of prickly achene fruits.

Annual or perennial herbs, often with stolons. Leaves submerged or not, linear-lanceolate to elliptic or cordate, often with transparent markings; stalks long. Flower heads globose, branched or unbranched. Flowers unisexual or bisexual. Sepals 3, persistent and sometimes enlarging in fruit. Petals 3. Stamens 6-30. Carpels several, spirally arranged. Fruit a head of achenes.

Grown either as aquarium plants or marginal ornamentals.

About 30 species from N and S America and Africa.

Division or seed.

Flowers and fruits in heads.

Source: Spencer, R. (2005). Alismataceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.