Small-flowered lupine is a small annual ranging from 10-40 cm in height with simple to freely branched stems. Its herbage is sparsely to densely covered with many short hairs and less numerous, longer brownish hairs. The leaves are compound palmate with 5-8 linear-oblanceolate leaflets with the individual leaflets 1.5-3 cm long. The upper leaf surfaces are hairless while the lower surfaces have appressed hairs . The leaf petioles are longer than the individual leaflets.
The inflorescence is a very short raceme of several flowers which is raised above the leaves. Individual flowers range from 7-9 mm long and are found on short pedicels from 1-2 mm long. The calyx lobes are unequal in length but are roughly 3 mm long. The upper calyx lobe is double-toothed. The petals are blue and the banner is often white-centered. Violet spots may or may not be found in the white banner. The banner is noticeably reflexed from the wings, and is roughly equal to the keel in length. The brownish pods range from 1.5-2 cm long and 3-5 mm wide and are covered with appressed hairs. 4-8 seeds may be found within the pods.
Bicolored lupine may be easily confused with miniature lupine Lupinus micranthus, but the former species has flowers with the banner reflexed further backwards so the space between the banner and wings is more open. The flowers of the latter species tend to be slightly shorter, ranging from 5-7 mm in length with the banner less reflexed.
Bicolored lupine is found growing in open prairies or gravelly areas at low elevations.
Small-flowered lupine is found west of the Cascade Mts. from British Columbia south to California.
It may be found in the Columbia River Gorge between the elevations of 100' to 700' between the Wind River and Dallesport, WA.