Bult Kroos (Lemna gibba) is a perennial aquatic plant that (nowadays) is considered one of the arum family (Araceae). The plant consists of a disc that a leaf-like stalk without leaves and a carrot. The 3-6 x 2-5 mm large slice of this plant is thick and spongy. Top of the disc is almost flat, strongly convex from below. If the disc is held against the light are seven to twelve large air cavities visible. The disc usually has five veins. Bult Kroos reproduces mainly vegetatively produced.

In the fall, starch is stored in the plant, after which it sinks to the bottom and there winters.

Bump Kroos blooms from April to July with green flowers.

The fruit is winged on the sides.

The plant is found in fresh to brackish, very nutrient-rich water.

Names in other languages:

• German: Wasser Bucklige Linse

• English: Fat Duck Weed

• French: Lentille d’eau bossue

Source: http://nl.wikipedia.org/wiki/Bultkroos

See also: International Flower Delivery, Florist