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

Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch

Astragalus whitneyi var. sonneanus

Synonym: Astragalus whitneyi ssp. hookerianus

Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows a cluster of the attractive, red-mottled pods of balloon milk-vetch as seen at the Squaw Creek Viewpoint off of Interstate 84 in northeastern Oregon................June 25, 2008. As they mature and dry out, they break away from the plant and are blown by the wind, eventually releasing their seeds as they shatter against rocks or other hard surfaces.

Flower of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)The photo at right shows a close-up of the flower of balloon milk-vetch as seen atop Lookout Mt., Ochoco NF............June 22, 1998.
Characteristics:

Also known as balloon pod milk-vetch, balloon milk-vetch is a perennial with with several to many branched stems that are spreading and clustered close to the ground. Plants range from 10-20 cm high and the foliage ranges from green to covered with silvery hairs. The compound-pinnate leaves are tufted close to the ground, measure 2.5-4 cm long, and bear 9-21 leaflets. Individual leaflets are narrowly oblong to obovate in shape 6-10 mm long. The upper surface of the leaflets ranges from glabrous to sparsely haired while the lower surface is covered with appressed hairs.

The flower stems are longer than the upper leaves and topped by a short, dense raceme of 5-20 flowers up to 1.5 cm long, and not elongating much in fruit. The tubular, bell-shaped calyx 4-5 mm long with triangular, awl-shaped teeth up to 2 mm long. The corolla is pinkish, lavender-purple, or yellowish and measures up to 1 cm long. The pod is greatly inflated, somewhat pear-shaped, clear with reddish or purple blotches over the surface. The pods measure 2.5-3 cm long and are very thin-walled and sparsely covered with minute, appressed hairs (See photos.).

Additional photos of balloon milk-vetch


Habitat:

Balloon milk-vetch is found on rocky outcrops and mountain crests at higher elevations, frequently on serpentine rock (especially in the Siskiyous). It is typically found between the elevations of 1300-3600 meters.


Range:

Balloon milk-vetch is widely distributed east of the Cascade Mts, from central Washington south to northeastern California, east to Nevada and southwest Idaho.


Flowers of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows a close-up of the flowers of balloon milk-vetch as seen at the Squaw Creek Viewpoint off of Interstate 84 in northeastern Oregon................June 25, 2008.

Inflated seed pods of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows an enlarged view of the inflated seed pods of balloon milk-vetch as seen at the Squaw Creek Viewpoint off of Interstate 84 in northeastern Oregon................June 25, 2008. Note the red mottling and numerous minute hairs on the surface of the pod.

Flower of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows balloon milk-vetch in bloom as seen at the Squaw Creek Viewpoint off of Interstate 84 in northeastern Oregon................June 25, 2008.

Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

Balloon milk-vetch blooming on serpentine gravels along the Canyon Mountain Trail #218, Strawberry Mountain Wilderness...............June 21, 2011.

Pinnately compound leaf of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus) - Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

Examples of balloonpod milkvetch as seen atop Baldy Mountain, Strawberry Mountain Wilderness............July 2, 2010.

Ovule of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows the inside of one of the pods, with the developing seeds. Photographed atop Baldy Mt., Strawberry Wilderness directly to the south of Prairie City, OR..........July 15, 2003.

Leaf of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows a close-up of the leaf of balloon milk-vetch as seen atop Lookout Mt., Ochoco NF............June 22, 1998.

Cluster of seed pods of Balloon Milk-vetch, Balloonpod Milkvetch, Balloon-pod Milk-vetch, Whitney's Balloon Milkvetch: Astragalus whitneyi var. sonneanus (Synonym: Astragalus whitneyi ssp. hookerianus)

The photo above shows a cluster of the attractive, red-mottled pods of balloon milk-vetch as seen at the summit of the Steens Mt. in southeastern Oregon...........July 28, 2004.

Paul Slichter