Trifid Bur-marigold

Trifid Bur-marigold - Bidens tripartita

Local name at Fucecchio Marshes: Parenti.

Large annual composite, typical of uncultivated areas subject to temporary flooding.

The dark green leaves are opposite and tripartite (i.e. divided into three parts, looking like three separate leaves), with toothed margins and the tips pointing downwards. Erect, much branched leathery stems, at first green then with reddish-brown hues. 

The yellow flowers are abundant but not very striking. But its fruit, or burs, certainly do not go unnoticed, which are much better known.

These are dark and flat with two hooked awns that enable it to catch onto the hairs of animals or our clothes.

This annoying characteristic, which is obviously a strategy for seed dispersal (zoochory) lies at the origin of the plant's popular Italian name of "parenti = relative" for the fruit, but sometimes extended to the plant as well.

In areas of advanced in-filling, the Trifid Bur-marigold often tends to be a weed and infests typical marshland plant formations, with summer its dominant season thanks to its copious dissemination and a surprisingly vigorous growth. 

The plant is spreading in all Italian fresh water wetlands.