Distribution: Occurring east of the Cascades crest in Washington; Washington to Oregon, east to Idaho.
Habitat: Open slopes and scablands in the foothills, valleys and plains, often with sagebrush.
Conservation Status: Not of concern
Low, glabrous perennial from a globose-thickened taproot, the leaves attached below the surface and the stem appearing scapose, up to about 1.5 dm. tall.
Leaves few, bi-ternately compound and pinnately-ternately dissected; petioles chaffy, sheathing; leaf blades broadly oblong in outline, 1.5-6 cm. long; ultimate leaf segments 10-40, linear, 0.5-1.5 cm. long. Thickened root is 1-2.5 cm. in diameter, brown, covered with bundles of rootlets.
Inflorescence a compact, compound umbel, the rays 0.5-3.5 cm. long; involucre none; involucel bractlets narrow, less than 2 mm. long; calyx teeth obsolete; flowers white with purple anthers; pedicels under 3 mm. long.
Fruit ovate, 4.5-8 mm. long and 3-5 mm. wide, the lateral wings 0.6-1.1 mm. wide.
Compared to L. gormanii, L. piperi has a stem leaf, smooth globose root and wide wing on the fruit.