Acmispon grandiflorus, synonym Lotus grandiflorus, is a species of legume native to western North America. It is known by the common name chaparral bird's-foot trefoil.
It is native to the west coast of North America from Washington to north-western Mexico, including California and Baja California, where it is found in many mountainous areas in the chaparral and coniferous forests.
Acmispon grandiflorus is a perennial herb taking an erect to decumbent form. It is lined with leaves each made up of oval leaflets 1 to 2 centimeters long and hairy to hairless in texture.
The inflorescence is made up 3 to 9 pealike flowers which may approach three centimeters long. The flower varies in color from whitish to yellow to pink.
The fruit is a legume pod up to 6 centimeters long.