[The Milk-vetch East of the Cascade Mts. of Oregon and Washington]

Lyall's Milk-vetch

Astragalus caricinus

Astragalus lyallii

The photo above shows the purple-lined banner and wings of Lyall's milk-vetch as seen on sandy ground along the Columbia River near Priest Rapids Dam, central Washington........April 30, 2007.

The photo at right shows a close-up of the flower of Lyall's milk-vetch as seen along the Columbia River about one mile north of the Vernita Bridge across the Columbia River in central Washington.........April 20, 2002. Note the distinctly reflexed banner and the long, linear, almost spidery calyx lobes.
Characteristics:

Lyall's milk-vetch is an erect perennial wildflower with several thin, branched stems clustered on a short, woody base and rising 10-20 cm high. The leaves and stems are variously pubescent, with grayish hairs that are soft, silky and appressed, stiff, sharp and appressed, or woolly and spreading. The ascending, pinnately compound leaves are 3-11.5 cm long with 11-21 leaflets that are lance-linear, linear-elliptic, or narrowly oblong in shape with acute, obtuse (lower leaflets) or rounded tips. The leaflets range from 8-15 mm long.

The loosely flowered racemes are axils and about equal to or longer than the upper leaves. The stout pedicels are 1 mm long while the woolly, bell-shaped calyx measures 5 mm long with linear teeth that are up to twice as long as the calyx tube. The whitish to pale lavender corolla is 6-8 mm long with purple-lined wings and banner. The narrow banner is well-reflexed and measures 4.5-7.5 mm long. The pod is lance-oblong in outline, slightly compressed, and 6-7 mm long and somewhat heart-shaped in cross-section. The pods are somewhat glabrous to woolly-haired.


Varieties of Lyall's Milk-vetch:

variety caricinus: Lower stipules clasping or joined with a fringed margin while the upper ones are triangular and not joined. Pods 6-8.5 mm long and 2-3 mm wide. Raceme shorter, flowering only from the upper 2-5 nodes.

variety lyallii: All stipules triangular, not joined. Pods 5-8 mm long and 2-3.5 mm wide. Raceme longer, flowering from the upper half of the stem.


Habitat:

Lyall's milk-vetch is found on sandy slopes and among sagebrush in the basin valleys and on low hillsides.


Range:

Lyall's milk-vetch is found from Kittitas County in central Washington south along the Yakima and Columbia Rivers to south-central Washington and upstream along the Snake River to southeastern Idaho and northeastern Malheur County in eastern Oregon.


The photo above shows a close-up of the upper stem and inflorescence of lyall's milk-vetch as seen in sandy soils south of Priest Rapids Dam.......April 30, 2007.

The photo above shows a close-up of a stem leaf of lyall's milk-vetch as seen in sandy soils south of Priest Rapids Dam.......April 30, 2007.

The photo above shows a close-up of the pinnately compound leaf of Lyall's milk-vetch as seen about 2 miles west of the Vernita Bridge on the east bank of the Columbia River in south-central Washington ........March 29, 2007.

The photo above shows a close-up of the leaflets of Lyall's milk-vetch as seen about 2 miles west of the Vernita Bridge on the east bank of the Columbia River in south-central Washington .........March 29, 2007. Note the numerous whitish hairs covering the surface of both the leaflets and stem.

The photo above shows the form of Lyall's milk-vetch as seen south of Priest Rapids Dam, central Washington.........April 30, 2007.

Lyall's Milk-vetch: Astragalus lyallii - Raceme of Lyall's Milk-vetch: Astragalus lyallii

Flowers of Lyall's Milk-vetch: Astragalus lyallii

What appears to be Lyall's milk-vetch (not. A. caricinus ?) as seen in a planting at the Horse Camp at Horn Rapids County Park, Benton County, Washington.............May 13, 2013.

Pods of Lyall's Milk-vetch: Astragalus lyallii - Pods of Lyall's Milk-vetch: Astragalus lyallii

What appears to be Lyall's milk-vetch as seen on Yakima Ridge (a closed area) in the Hanford Reach National Monument.........May 12, 2013.

Paul Slichter