Rorippa amphibia

Water - cress ( Rorippa amphibia )

The water - cress ( Rorippa amphibia ), also referred to as bank - cress, watercress or cress pond, is a very scattered in Central Europe occurring member of the cabbage family ( Brassicaceae). It flowers mainly by May to August.

• 2.1 for location
• 2.2 General distribution
• 2.3 Spreading in Germany

Appearance

The perennial herbaceous plant reaches a height of about 50 to 150 cm. The stem grows low to high, is bald, branched and has partly prostrate, suckering like to bewurzelnde stems. The lower stem leaves are pinnate to a comb with straightedge to lanceolate, acute segments. They are narrowed into a short stalk and about 7 to 15 cm long. The upper stem leaves are sessile, linear to lanceolate and at the bottom have little or no auriculate. You are almost entire, dentate to sharp. Sepals are about 2.5 to 4 mm long. The petals are golden, about 3.5 to 6.5 mm long, obovate and rounded. The fruit is oval, approximately 2 to 5 mm long and 1-3 mm wide. She sits at about 8 to 15 mm long, horizontal to slightly downward curved stems.

Variability of the species

The leaf shape is highly variable. When water forms the stems are thick, hollow, tubular and not furrowed.

Occurrence

Habitat requirements

The water - cress grows in swamps, on rich, often muddy and at times dry -falling floors of standing or slow- flowing waters.

Popularization

Rorippa amphibia occurs practically throughout Europe and Asia. She is a Eurasian Florenelement. In Austria you can find the kind scattered until rare. In Switzerland, it also happens very scattered.

Distribution in Germany

The water - cress is in the north of the territory scattered up partially before widespread. In the rest of it is scattered to rare to find.

Others

The flowers are pollinated by insects. A vegetative reproduction is, however, easily broken by shoot pieces possible.