General:
Perennial herb from a thick woody rhizome; stems erect to ascending, 10-40 cm tall, mostly unbranched, appressed-hairy to nearly glabrous.

Leaves:
Alternate, palmately compound, stalked; leaflets 3, oblanceolate to elliptic, 1.5-3 cm long, short-hairy on both surfaces or glabrous above; lowest stipules papery, sheathing, the upper ones large, egg-shaped, resembling leaflets, joined to the leaf-stalk at the base.

Flowers:
Inflorescence a dense, stalked, erect, terminal raceme, 5-10 cm long, of 10 to 30 erect, pea-like flowers; corollas bright yellow, 17-25 mm long; calyces bell-shaped, 8-13 mm long, 2-lipped, the upper lip 2-toothed, the lower 3-toothed, the teeth triangular.

Fruits:
Pods, linear, flattened, 4-8 cm long, spreading and curved, stiff-papery, usually soft-hairy; seeds several.

Source:  The Illustrated Flora of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  The Illustrated Flora of British Columbia

Synonyms and Alternate Names:
Thermopsis arenosa A. Nels.
Thermopsis montana var. ovata (B.L. Rob. ex Piper) H. St. John
Thermopsis ovata B.L. Rob. ex Piper
Thermopsis rhombifolia var. annulocarpa (A. Nels.) L.O. Williams
Thermopsis rhombifolia var. arenosa (A. Nels.) Larisey
Thermopsis rhombifolia var. ovata (B.L. Rob. ex Piper) Isely
Thermopsis rhombifolia var. rhombifolia