Common birds-foot-trefoil (Lotus corniculatus)
Collins, 136; Readers Digest, 119
This cheery perennial flowers from May to September in hayfields and grassy banks on our downland. The flowers are a bright yellow often tinged with orange or red. It is very abundant in the hayfields of Bodsham. It is also known as ‘Ladies Shoes and Stockings’ and ‘Crow-Toes’. The name Bird’s-Foot reflects the similarity of its pods (see below) to a bird’s claw. The plant is one of the staple diets for the Green Hairstreak and Dingy Skipper butterflies.
See also: http://www.maes.umn.edu/maespubs/vartrial/pdfpubs/1999bird.pdf
An example below of a yellow only flower