Greek speira – spiral, delos – obvious.

Floating herb often aggregated into groups of 2-5 or more plants. Body flattish, ovate to elliptic or slightly kidney-shaped, the lower surface often tinged purple. Marginal pouch on lower surface near the margin. Roots 2-18. Flower cluster of 1 female and 2 male flowers together in a bract.

Grown in aquaria and tolerating a wide range of water temperatures. Spreading rapidly.

4 species from temperate and tropical areas.

Budding.

Used as a supplement in stock feed and sometimes as a nutrient sink.

Roots 2 or more; veins 3 or more; lower surface often purplish.

Source: Spencer, R. (2005). Lemnaceae. 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.