Bidens cernua

Nodding Bidens ( Bidens cernua ) Copy without ray florets

The nodding bur-marigold ( Bidens cernua ) is a flowering plant in the sunflower family ( Asteraceae).

Description

The nodding bur-marigold grows as an annual, herbaceous plant and reaches a height of 10 to 90 cm. The stem is erect and often of a yellow-green color. The leaves are elongated - lanceolate, undivided and fused together in pairs at the base. They are sharply toothed, light green, glabrous or sometimes hairy at the top of something.

The solitary flower heads have a diameter of about 30 mm. Especially when they start fading " nod " to. The bracts are arranged in two rows, the outer leaves are formed leaf-like and much longer than the inner ones. These are broadly ovate and brown green color. The chaff leaves are as long as the fruit and the awns. Ray florets, when present, stained yellow, but can often be missing. The tubular flowers are colored more golden yellow. The achene is in cross-section three - to four -edged and has four awns.

The flowering period extends from July to September. The chromosome number is 2n = 24

Dissemination

Popularization

Bidens cernua arrives in Europe, through the Balkans to northern and eastern Asia. He is a Eurasian- continental Florenelement. In Austria and Switzerland, the species is scattered to find.

Distribution in Germany

The Nodding Two tooth comes in the whole area scattered to widespread ago. In the Alps, he rises to altitudes of 800 meters.

Habitat requirements

The nodding bur-marigold grows in Ufersaumgesellschaften, ditches, ponds, swamps, fens and wet fields. He prefers wet, nutrient - and nitrogen-rich mud and clay soils.