Bidens tripartita

Tripartite bur ( Bidens tripartita )

The Bidens tripartita ( Bidens tripartita ) is a flowering plant in the sunflower family ( Asteraceae). It is distributed in Eurasia.

Description

The Bidens tripartita grows as annual herbaceous plant and reaches a height of 15 to 100 centimeters. The upright stem is often crowded brownish, glabrous or slightly hairy fluffy and provided with numerous long, spreading branches. The leaves are usually three, rarely up to five parts pinnate, dark green and narrowed into a winged stalk. The middle leaves are larger and often shared columns. The tip is serrated lanceolate and coarsely.

The solitary flower heads are at least as high as wide and have a diameter of about 15 to 25 millimeters. The outer bracts are usually five to eight foliage leaf -shaped and longer than the head. The inner bracts are colored oval brown and yellow. The chaff leaves are broad - linear and only reach the base of the awns. Ray florets are usually absent. The tubular flowers are of a brownish-yellow color.

The achene is smooth, in contrast to neophytic Schwarzfrüchtigen Two tooth without warty bumps on the sides and only marginally more or less backward rough - prickly. It has two to four awns.

Ecology

The Bidens tripartita is a sommerannueller Therophyt and a marsh plant, the deeply rooted to 50 centimeters.

The flowers are "basket flower "; since the ray florets usually missing, you accept kronblattartigen bracts the show function. The pollinators are bees, bumblebees and hoverflies. The heyday of this short-day plant ranges from July to November.

The fruits are oblong- wedge-shaped, flattened achenes without pappus. The 2 (-3) grannenartigen fruit appendages with their barbed bristles cause their Velcro propagation; the flow of water as water Hafter is due to the non-wettability, the smooth surface and the flattened shape of the achenes; next processing distribution is carried out by seed eaters, for example by goldfinches.

Occurrence

Biden is tripartita throughout Europe, North and Central Asia spread. It also occurs in Australia.

In Austria, this type is most commonly found, but endangered in the western Alps, in Switzerland, she is absent-minded.

The Bidens tripartita comes in Germany in the northern lowlands and the valleys of the central and southern region spread to absent-minded. In addition, it is scattered to rare. In the Alps it reaches to ascending at an altitude of 800 meters.

The Bidens tripartita grows in Ufersaumgesellschaften, ponds, pools, ditches, swamps and fields. He usually prefers wet, nutrient - and nitrogen- rich, open clayey mud and sandy soils.