Also known in some forms as yellow locoweed, field crazyweed is a variable species of perennial wildflower that resembles smaller forms of Oxytropis sericea. The leaves and stems are thinly to densely covered with long, weak, spreading hairs. The pinnately compound leaves bear 7-41 leaflets. The leaflets are narrowly ovate to oblong-elliptic in shape and typically measure from 3-20 mm long.
The flower stems are about as long or longer than the longer leaves, and are ascending and somewhat incurved. They are topped by dense racemes of 3-40 flowers. The calyx is variable, measuring from 5-7.5 mm long with linear-oblong teeth from 1-4 mm long. The sinuses between the calyx teeth are rounded. The calyx is typically loosely covered with long, weak, spreading hairs that are grayish to blackish. The corolla measures 10-20 mm long and varies (with variety) from white, to cream, yellowish to lavender or purplish. The keel is sometimes spotted with purple. The erect to ascending pods are sessile or with short pedicels and are more membranous than fleshy. The pods are 1-2.5 cm long and narrowly oblong-ellipsoid in outline tapering to a beak up to 5 mm long.
variety columbiana: Corollas white, the keel strongly purple-spotted. Leaflets generally number less than 17, but may number up to 23. Found along gravel bars or stony river or lake shores from near the confluence of the Spokane and Columbia Rivers of northeastern Washington north into Canada and east to the Flathead Lake region of western Montana.
variety cusickii: Corollas cream in color (whitish-yellow), the keel not purple-spotted. Leaflets typically number less than 17. Flower stems typically measure less than 15 cm long. Stipules at the base of the leaves glabrous or nearly so. Found east of the Cascade Mts. in Washington east to Alberta and North Dakota and south through the Rocky Mts. to Colorado.
variety spicata: Corollas cream in color (whitish-yellow), the keel not purple-spotted. Leaflets typically number more than 17. Flower stems typically measure greater than 15 cm long. Stipules at the base of the leaves very hairy. Found from western Washington east to Alberta and North Dakota and south through the Rocky Mts. to Colorado.
variety spicata (O. sericea var. spicata): Corolla lemon to sulphur yellow, the keel typically not purple-spotted. Found north-central or northeastern Washington to northern British Columbia and east to central Idaho and northern Wyoming.
variety wanapum: Corollas pale lavender. Leaflets typically average 22 in number. Plants tend to have longer flower scapes and longer leaves and leaflets than var. columbiana, cusickii, & var. gracilis. Found only on Saddle Mt. in Grant County, central Washington.
Field crazyweed may be found in rocky ledges, on talus or in meadows or high altitude prairie on subalpine to alpine peaks or ridgetops, Several varieties are found only above 2100 meters, while one is found on gravel bars along the Columbia River.
Field crazyweed may be found from northern British Columbia south to the east of the Cascade Mts. into central and eastern Washington, and further south to the Wallowa Mts. of northeastern Oregon. Plants may be found eastward through central Idaho to the Rocky Mts., where they are found from Alberta south to northern Colorado.