Looking at the kidney vetch (Anthyllis vulneraria) flower one gets the impression it has a fungal infection or has, perhaps, been attacked by a gall wasp because in amongst the familiar yellow vetch flower heads are masses of white hairs. This is actually perfectly natural and it is this feature that makes kidney vetch unique and unmistakable.
Flowering from May until September the flowers are classic clover-shaped which confirms it as a member of the Fabaceae or pea family. The head is made up of a cluster of typical pea shaped flowers that start with an orange tint but quickly become a bright yellow before withering to a reddish brown. Often you can find all three stages on the one flower. It is the fluffy material between these flowers that makes it easily distinguished from its cousins in the clover family.
It is a sprawling plant that does not grow very tall and it likes dry, open grassland; usually on chalk or limestone and frequently on sea cliffs. Where it occurs it can be abundant. It is the food plant pf the small blue butterfly and they live in close association with each other.