Page authors: Don Knoke, David Giblin
Astragalus riparius
Piper's milk-vetch

Distribution: Occurring east of the Cascades crest in the southeastern counties in Washington; southeastern WA east to adjacent Idaho.

Habitat: Dry bluffs and canyon banks.

Flowers: May-June

Origin: Native

Growth Duration: Perennial

Conservation Status: Threatened in Washington (WANHP)


Gray or greenish perennial from a woody taproot and crown, the erect stems tufted, 4-15 cm. long.


Leaves alternate, pinnate, 1-2 dm. long; leaflets 21-33, linear-oblong to narrowly oblanceolate, 4-21 mm. long, glabrous above; stipules 2.5-7 mm. long, papery, clasping but free.


Inflorescence of 10- to 20-flowered racemes, the peduncles stout, 14-30 cm. long, surpassing the leaves; pedicles ascending, 2-5 mm. long; flowers pale yellowish to greenish-white, drying yellowish; calyx 7-10 mm. long, with fine, black hairs, the 5 teeth 2-5 mm. long; banner 11.5-14 mm. long, recurved, the margins becoming lacerate, the wings longer than the banner; stamens 10.


Pod erect, sessile, oblong-ellipsoid, 1.5-2.5 cm. long and 6-10 mm. thick, with a rigid beak.

Accepted Name:
Astragalus riparius Barneby
Publication: American Midland Naturalist 55(2): 490-491. 1956. 1956.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Astragalus riparius in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Astragalus riparius checklist entry.

E-Flora BC: Astragalus riparius atlas page.

CalPhotos: Astragalus riparius photos.

USDA Plants: Astragalus riparius information.

1 photographs:
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