Lupinus sulphureus (sulphur lupine, sulphur-flower lupine)[1] is a species of lupine, a flowering plant of the legume family, Fabaceae.
It is a perennial herbaceous plant growing to 40 to 80 cm tall. The leaves are palmately compound, with 7 to 13 leaflets each 2 to 5 cm long. The flowers are produced in whorls on a spike 12 to 20 cm long.
There are three subspecies:
It is native to western North America from southern British Columbia south through Washington to Oregon.
Fender's blue butterfly, an endangered species, is host-specific on Kincaid's lupine. Its larvae eat the leaves during the fall and spend the winter among the roots. In spring, the larvae continue to feed on the leaves before pupating.