Page authors: Don Knoke, David Giblin
Astragalus diaphanus
John Day milk-vetch, transparent milk-vetch

Distribution: Known historically from Klickitat County in Washington, but now thought to be extirpated; Klickitat County, Washington south to Wheeler and Grant counties in Oregon.

Habitat: Gravel bars, alluvial slopes, and in thin gravelly soil overlying basaltic rock.

Flowers: May-June

Origin: Native

Growth Duration: Annual, Biennial

Conservation Status: Presumed extirpated in Washington (WANHP)


Prostrate annual or biennial from a stout taproot, nearly glabrous, the stems numerous, 1-4 dm. long.


Leaves alternate, pinnate, 2-4 cm. long; stipules 1-2 mm. long, not connate; leaflets 9-13, obovate, 4-12 mm. long.


Inflorescence of 5- to 20-flowered compact racemes; peduncles about equaling the leaves; flowers 4-8 mm. long, mostly white, but the banner purplish-veined and the keel purplish-tipped; calyx 2-3 mm. long, the 5 teeth purplish, linear, shorter than the tube.


Pods sessile, linear-oblong in outline, strongly curved, membranous, 1.5-2 cm. long and 3-4 mm thick, cordate and 2-celled in cross section due to the complete intrusion of the lower suture.

Accepted Name:
Astragalus diaphanus Douglas
Publication: Fl. Bor.-Amer. 1(3): 151. 1831. 1831.

Synonyms & Misapplications:
Astragalus diaphanus Douglas var. diaphanus
Astragalus diaphanus Douglas var. diurnus (S. Watson) Barneby ex M. Peck
Additional Resources:

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

WA Flora Checklist: Astragalus diaphanus checklist entry.

E-Flora BC: Astragalus diaphanus atlas page.

CalPhotos: Astragalus diaphanus photos.

USDA Plants: Astragalus diaphanus information.

21 photographs:
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