Bidens frondosa
Inflorescence a Schwarzfrüchtigen Two tooth ( Bidens frondosa )
The Schwarzfrüchtige Bidens ( Bidens frondosa, Syn: Bidens melanocarpa ) is a plant from the sunflower family ( Asteraceae).
- 2.1 General distribution
- 2.2 Spreading in Germany
- 2.3 for location
Description
Vegetative characteristics
When Schwarzfrüchtigen Bidens is an annual herbaceous plant that reaches a height between 30 and 120 cm, but in exceptional cases the reeds and up to 3 m can be high. This type usually grows from the base of highly branched with upwardly inclined branches. The stalk is often discolored purple. The against-constant leaves are long-petiolate and usually in three parts (up to five parts ) feathered. The lanceolate leaves are clearly cut and sitting with verschmälertem, often asymmetrical base of the leaf stem. The leaves are in contrast to the three -part Two tooth and the tooth completely separated into two radiating leaflets.
Generative features
The flowering period extends from August to September. The cups are surrounded by five to eight unequal bracts, which are usually narrow lanceolate. The bracts of the cups, however, are dyed reddish sometimes broadly oval and at the top. The flower heads, which have a diameter of 5 to 10 mm, containing only yellow tubular flowers. On the inflorescence ground between the tubular flowers are blackish, dry chaff leaves. Ray florets absent.
The flat, blackish to blackish - brown achenes are bumpy on the surface. On top of the achenes sit grannenförmige two teeth that are staffed by generally rearward-facing spines.
The chromosome number is 2n = 48
B. frondosa var frondosa ( herbarium )
B. frondosa var frondosa (inflorescence with fruits )
The Bidens frondosa var variety anomala
Less than the nominate mostly occurring Bidens frondosa var frondosa Bidens frondosa is the variety var anomala. In Bidens frondosa var anomala the awns of the fruit, in contrast to variety Bidens frondosa var frondosa are provided with upwardly directed spines.
Bidens frondosa var anomala ( habitus )
Bidens frondosa var anomala (inflorescence)
Bidens frondosa var anomala (fruits)
Occurrence
Popularization
The home of Bidens frondosa is the eastern North America. Meanwhile, he has also spread in Europe as a neophyte. The distribution ranges from Portugal and Spain, France and the Netherlands to Italy, Bosnia, Austria, Czech Republic, Hungary and Poland. It shows a sub-Mediterranean - subatlantic spread tendency. In Austria you can find this kind scattered to moderately frequent along the great rivers, in Switzerland it is naturalized in southern Ticino.
Distribution in Germany
The Schwarzfrüchtige Two tooth is absent-minded in the northern area along the major rivers. Part of it is quite common to be found there also. He penetrates increasingly facing into the central and southern area, especially along the navigable rivers. Only on the Danube he is only rarely found.
Habitat requirements
The Schwarzfrüchtige Two tooth grows on the banks hemming, rivers, ditches, ponds, lakes, roadsides, etc. It prefers moist to wet, sometimes flooded, nutrient - and nitrogen-rich, muddy soil. He rarely found even in dry waste places.