Photos: Arne Ader
The daisy family (Compositae) is incredibly large, the oxeye daisy as well as sunflower, dandelion and burdock belong there ....
Knapweeds are perennial plants while the very similar cornflower is an annual: lower and with a more delicate appearance. Among both species pink as well as white flowers occur.
The brown knapweed can be confused with the taller-growing greater knapweed (Centaurea scabiosa), but the flowers of the latter are larger, with a more lilac colour, the leaves are deeply and pinnately lobed. The leaves of the brown knapweed generally have entire margins, occasionally with small serrations. At the edges of the flowerheads (capitula) of the knapweeds are funnel-shaped florets; they must attract pollinators, but they have neither pistil nor stamens - these ray florets are sterile. Insects carry the pollen from one flower to others; in the centre of the daisy family flowerheads are the disk florets that have a pistil as well as stamens – so the disk florets take care of a next generation of knapweeds.
Both the knapweeds and the cornflower are weeds but very beautiful weeds.