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NATURAL HISTORY

COACHELLA VALLEY MILK VETCH } Astragalus lentiginosus var. coachellae
FAMILY: Fabaceae

DESCRIPTION: The Coachella Valley milk vetch is an erect winter annual herb that grows eight to 12 inches high. The plant is densely covered with silky, white hairs, and it produces flowers that range from pink to deep magenta. Leaves range from two to four inches long and have up to 21 pear-shaped leaflets. This species is distinguished by its strongly inflated, two-chambered, egg-shaped, mottled pods.

HABITAT: The Coachella Valley milk vetch occurs in dunes and sandy flats alongside disturbed margins of washes, as well as in coarse, sandy soils along roadsides. It may also be found in sandy substrates in creosote bush scrub not directly associated with sand dune habitat. This species lives at elevations ranging from 200 to 2,100 feet.

RANGE: The species is restricted to fewer than 25 locations in the Coachella Valley in Riverside County, California. Between Cabazon and Indio, its east-west range is approximately 33 miles, with the exception of six outlying occurrences within a five-mile area of the Chuckwalla Valley.

LIFE CYCLE: Coachella Valley milk vetch flowers bloom between February and May. Seed pods fall to the ground when dry and blow along the sand dunes to disperse seeds.

THREATS: Habitat destruction due to continuing urban development is the primary threat to the Coachella Valley milk vetch. While fragmenting dune habitat, development interferes with the windblown sand transport system that is vital to dune ecosystems. Other impacts include off-road vehicle use, trampling, wind energy farms, sand and gravel mining, dams, and the introduction of nonnative plants, including Russian thistle and tamarisk.

POPULATION TREND: The Coachella Valley milk vetch population varies widely from year to year, depending on environmental and drought conditions. This makes an assessment of the total number of individual plants difficult. Historical abundance is unknown. During years of heavy rainfall, hundreds to thousands of individuals have been reported in a single area, yet during drought conditions, records of fewer than 20 plants are common.

Photo courtesy of California Department of Fish and Game