[Milkvetches: The Genus Astragalus East of the Cascade Mountains of Oregon and Washington]

Yakima Milkvetch, Yakima Milk-vetch

Astragalus reventiformis

Synonyms: Astragalus reventus var. canbyi, Cnemidophacos reventiformis

Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

The photo above shows a close-up of the inflorescence of Yakima milk-vetch as seen on the southern edge of Fort Simcoe State Park, several miles to the southwest of White Swan, WA........April 5, 2008.

Leaf of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)Photo at right of leaf of Yakima milk-vetch atop the Horse Heaven Hills west of Richland, WA......April 17, 1998.
Characteristics:

Yakima milk-vetch is an attractive perennial wildflowers with several to many clustered stems from 2-20 cm high. The stems and leaves are greenish to grayish in color, and when bearing hairs, sparsely haired with minute, straight, stiff, sharp and appressed hairs. The 17-37 leaflets on the pinnately compound leaves are narrowly linear and measure up to 25 mm long and up to 2-3 mm wide.

The fairly stout flower stems hold the terminal racemes equal to or higher than the highest leaves. The flower racemes are tightly to loosely clustered, with 7-35 flowers. The flowers are yellow-white to purple-tinged. The banner is held upwards at an angle up to about 45 degrees and is longer than the wings. The thin wings are in turn longer than the keel. The bell-shaped calyx is covered with grayish to black hairs and measures 8-12 mm long, with thin, awl-shaped teeth 2.5-5 mm long. The glabrous pod is held erect and measures from 1.5-3 cm long.


Similar Species:

Idaho Milk-vetch: Astragalus conjunctus - Caylx cylindrical, 6-15 mm long, about 2 times as long as thick. Calyx teeth 1.5-3 mm long. Corolla white or with purplish tip to keel and banner. Leaflets 13-31. Pod glabrous. Found from Wasco County, northcentral Oregon east to the Blue mts. and south to the the Steens Mt. and east to southwestern Idaho.

Hood River Milk-vetch: Astragalus hoodianus - Calyx bell-shaped, 11-15 mm long, about 1.5 times as long as thick. Calyx teeth 4.5-7.5 mm long. Leaflets 17-37. Pod pubescent. Found near the Columbia River Gorge in Wasco and Hood River Counties in Oregon and Klickitat County in Washington.

Yakima Milk-vetch: Astragalus reventiformis - Calyx bell-shaped, 8-12 mm long, about 1.5 times as long as thick. Calyx teeth 2.5-5 mm long. Leaflets 17-37. Pod pubescent. Found from Kittitas County in Washington near Ellensburg south to Klickitat County, Washington and south into Sherman County of Oregon.

Blue Mt. Milk-vetch: Astragalus reventus - Leaflets 23-41. Pod glabrous. Found in the Blue Mts. of northeastern Oregon near the headwaters of the Umatilla and Grande Ronde Rivers into southeastern Washington.

Sheldon's Milk-vetch: Astragalus sheldonii - Leaflets 23-41. Pod usually pubescent. Found from southern Asotin County in southeastern Washington south into Wallowa County, northeastern Oregon and into Lewis and Nez Perce Counties in Idaho.


Habitat:

Yakima milk-vetch may be found growing in the sagebrush desert, scablands, grasslands, ponderosa forests, and stony flats from the foothills into the lower mountains.


Range:

Yakima milk-vetch is distributed in the Yakima River drainage, from Ellensburg, WA south to the Horse Heaven Hills and Columbia Hills along the Columbia River. Evidently it is found at one spot on the Oregon side of the river in Sherman County.


Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Inflorescence of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Flower of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Seed pods of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Yakima milk-vetch as seen along US Highway 97 about 10 miles east of Satus Pass, Yakima County, Washington...........April 28, 2014. Note the banner which is swept back about 90 degrees from the main axis of the flower, the wing petals which are longer than the keel, and the glabrous pods.

Inflorescence of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Flower of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Dry fruit pods of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Maturing fruit pods of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Maturing fruits of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Inflorescence of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Leaf of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Yakima milk-vetch observed on Bickleton Ridge in the Simcoe Mountains Unit of the Klickitat Wildlife Area. The uppermost set of photos were taken May 7, 2017. The middle set were taken May 7 (left and June 17, 2017 (right). The lower trio of photos were taken May 28, 2017.

Inflorescence of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Inflorescence of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

Close-up images of the inflorescence of yakima milk-vetch observed on scablands above Wenas Campground, Yakima County, Washington........May 24, 2019.

SEed pods of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

The photo above shows the glabrous pods of Yakima mil-vetch as seen near Maryhill, Washington in the Columbia River Gorge........May 5, 2001.

Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis) - Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonyms: Astragalus reventus var. canbyi, Cnemidophacos reventiformis) - Inflorescence of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonyms: Astragalus reventus var. canbyi, Cnemidophacos reventiformis)

The photo at left shows Yakima milk-vetch as seen at the southwestern edge of Fort Simcoe State Park, several miles to the southwest of White Swan, WA.........April 5, 2008. The photo at center shows Yakima milk-vetch blooming along a jeep road north of Box Canyon Road in the Simcoe Mountains Unit of the Klickitat Wildlife Area......May 10, 2021. The photo at right shows Yakima milk-vetch blooming south of Box Canyon Road near the north rim of Rock Creek canyon in the Simcoe Mountains Unit of the Klickitat Wildlife Area.....April 15, 2021

Flower of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

The photo above shows a close-up of the flowers of Yakima milk-vetch as seen in the Columbia Hills to the north of The Dalles, OR........June 1, 1997. The flowers may be yellowish or whitish as seen in the photo below. Note in both photos the very long wings (much longer than the keel) and the banner that is well reflexed away from the axis of the keel.

Flower of Yakima Milk-vetch: Astragalus reventiformis (Synonyms: A. reventus var. canbyi, Cnemidophacos reventiformis)

The photo above shows another close-up of the flower of Yakima milk-vetch as seen along US 97 east of Satus Pass, Washington.......May 10, 1997.

Paul Slichter