Species Spotlight: Jaeger’s Milkvetch Named After Local Biologist
The Jaeger’s milkvetch (Astragalus pachypus var. jaegeri) is one of 28 plant species and subspecies named for biologist, educator, and environmentalist Edmund Carroll Jaeger, who made his mark on western Riverside County. Dr. Jaeger taught zoology at Riverside City College (RCC) for 30 years and became Curator of Plants at the Riverside Municipal Museum after he retired from RCC in 1952.
In 1946, he confirmed that birds can hibernate through a groundbreaking study of the desert poorwill, a discovery that was featured in National Geographic magazine. Jaeger became known as the “dean of the California desert” for his teaching of desert ecology, a lifetime of ecological research, plant and animal photographs, and authoring several popular nature books written throughout his career.
Local occurrences of Jaeger’s milkvetch were historically found in southern Riverside and northern San Diego counties, with more current observations in northern portions of Riverside County. This milkvetch prefers dry ridges and valleys with open sandy or rocky slopes within coastal scrub, chaparral, and grasslands at low elevations. Jaeger’s milkvetch has been found in areas along the Agua Tibia Wilderness near Vail Lake, the foothills of the San Jacinto Mountains, Aguanga Valley, and Potrero Creek; it thrives in our arid climate that experiences spells of dry weather.
Jaeger’s milkvetch is a shrubby perennial that can grow up to 31 inches tall. It blooms from December through June with flowers that vary in color from clear to light yellow. As a member of the pea or legume family, they produce long pea-shaped seed pods that grow up to an inch long.
Threats to Jaeger’s milkvetch include urbanization, agricultural conversion, and livestock grazing. With the help of the MSHCP, at least 249,440 acres of land will be conserved in this species’ suitable habitat of chaparral, grassland, coastal sage scrub, and woodland/forest. Conserved habitat will protect this species and enable it to expand into other areas of suitable habitat.