[Milk-vetches: The Genus Astragalus in the Columbia River Gorge of Oregon and Washington]

Yakima Milkvetch, Yakima Milk-vetch

Astragalus reventiformis

Synonym: Astragalus reventus var. canbyi

Sideview of the calyx and corolla of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

The photo above shows a close-up side view of the calyx and corolla of Yakima Milk-vetch as seen in the Columbia Hills in the eastern Columbia River Gorge........May 14, 2006. The petals in this species seem to range from white to a light, creamy yellow. A diagnostic feature of this species in the Gorge is the banner which is held erect or swept back nearly 90 degrees from the wings and keel.

The photo at right shows a frontal view of the wings and erect banner of Yakima milk-vetch as seen in the Columbia Hills.........May 1, 2005. Note that the banner is fairly deeply notched, a characteristic of this species.
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 (Tygh Ridge), 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. Banner held erect 90 degrees from wings and keel, generally notched at tip. Leaflets 17-37. Pod generally glabrous, but may be lightly 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 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. The other varieties may be found from central Washington south to north-central Oregon, eastward to the Steens Mt and southwest Idaho.

In the Columbia River Gorge, it may be found between the elevations of 300'-2400' in the Columbia Hills from west of Stacker Butte eastward to Haystack Butte and beyond.


Sideview of the calyx and corolla of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Sideview of the calyx and corolla of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Ventral view of glabrous pod of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Sideview of the glabrous pod of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Close-up views of the flowers and pods of Yakma milkvetch as seen along the Roosevelt Grade Road above Roosevelt, WA..........April 25, 2010.

Pinnately compound leaf of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

The pinnately compound leaf of Yakima milk-vetch as seen in the Columbia Hills.........May 14, 2006.

Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Basal leaves of a young Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Yakima milk-vetch as seen high up in the Columbia Hills State Park...........April 12, 2014. The photo at right shows the appearance of the basal leaves of a young plant.

Glabrous pods of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

The photo above shows a close-up of the glabrous seed pods of Yakima milk-vetch as seen in the Columbia Hills.......June 3, 2006.

Frontal view of flower of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

A frontal view of Yakima milk-vetch as seen from the Columbia Hills.........May 14, 2006.

Sideview of the calyx and corolla of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

The photo above shows a close-up side view of the calyx and corolla of Yakima Milk-vetch as seen in the Columbia Hills in the eastern Columbia River Gorge.........May 1, 2005.

Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Yakima milk-vetch blooming at a pass along the Bickleton Highway between Bickleton, WA and Mabton, WA..........April 23, 2013.


Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Fruits of Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

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

Yakima milk-vetch blooming in the northwest corner of the Columbia Hills State Park..........April 16, 2015.

Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Yakima milk-vetch as seen in the northwest corner of the Columbia Hills State Park..........October 18, 2015.

Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi) - Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

Yakima milk-vetch in bloom along trails below the Dalles Mt. Ranch trailhead at Columbia Hills Historical State Park.......May 2, 2018.

Yakima Milkvetch, Yakima Milk-vetch: Astragalus reventiformis (Synonym: Astragalus reventus var. canbyi)

The photo above shows Yakima milk-vetch in the Columbia Hills of the eastern Columbia River Gorge.........May 1, 2005.

Paul Slichter