Scientific name: Lemna aequinoctialis Welwitsch

Common name: Common duckweed

Family: Lemnaceae

Origin:

North America and elsewhere.

Habit:

Very small plant, less than 5 mm long, found floating on the water surface.

Habitat:

Found in garden ponds and other bodies of standing or slow-moving water.

General description:

Stems and leaves

The plant consists of a green, flattened, oval, leaf-like structure (ie. 'plant body') 2 to 3.5 mm in size that floats on the water surface, and a small root found below the water. Vegetative reproduction occurs by 'budding' at either side of the basal end of the plant body. This leads to small clusters of these plants forming on the water surface which readily separate.

Flowers and fruit

This plant has very inconspicuous and membranous flowers. They are borne singly inside small pouches near where the 'budding' occurs and consist of a pistil (ie. ovary, style and stigma) and two stamens. Tiny seeds are produced.

Distinguishing characteristics:

A small, green floating plant less than 5 mm long. The 'plant body' resembles a small leaf with an entire margin. May be confused with Azolla spp. but does not branch like this species and hence does not have a ferny appearance.

Noxious status:

Not noxious.

Sources:

Stanley, T.E. and Ross, E.M. (1983-1989). Flora of South-eastern Queensland. Volume 3. Department of Primary Industries, Brisbane.