Knautia arvensis

Plants are 30 to 100 cm tall, with bristly hairs of unequal length, with or without glands.

Lower leaves are mostly undivided and lance-shaped, while upper leaves are mostly deeply pinnately lobed.

The flat flower head is 2 to 4 cm across; flowers are blue to red-violet, and the outer flowers are larger than the inner ones.

Info Flora gives May to September as the flowering period in Switzerland.

The Czech Pladias database gives June to September as the flowering period.

In Switzerland it grows in meadows, on banks and along paths, from the colline to the montane belt, sometimes subalpine.

Pladias lists bumblebees, solitary bees, hoverflies and butterflies as its main pollinator groups.

According to a Swedish study, the solitary bee Andrena hattorfiana specialises in collecting pollen from the scabious family (Dipsacaceae).

A Swedish study states that in northern Europe field scabious is the main pollen source of Andrena hattorfiana.

In a Swedish study, researchers estimated that one average nest with six cells needs pollen from about 72 flower heads, or 11 plants.

The British recording society states that scabious, especially field scabious, is a necessary requirement for Andrena hattorfiana.

In Britain, males of Andrena hattorfiana show a marked preference for field scabious flowers.