Dean's Milk Vetch [Astragalus deanei (Rydb.) Barneby]

Dean's Milk Vetch [Astragalus deanei (Rydb.) Barneby]

Listing CNPS List 1B R-E-D Code 3-3-3

State/Federal. Status -- /C2 FABACEAE Mar.-May

Global Rank G2 State Rank S2.1

Distribution: San Diego County

Habitat: Diegan Sage Scrub, chaparral, and sandy washes are all reported habitats for this very rare, herbaceous perennial. The few extant locales examined showed this species to utilize the partial shade of low-growing shrubs where Dean's Milk Vetch was not readily detectable. Cieneba-Fallbrook rocky sandy loam is the soil type mapped for the Tecate population.

Known Sites: The current status of historical sites in Sloane Canyon and at the Singing Hills Country Club are unknown; much of the habitat is developed or degraded. A few plants are reported just west of a sharp northeastward turn on Willow Glen Drive 1 mile south of the Singing Hills Golf Course. It was noted northeast of Hillsdale Road near the intersection with Donohue Drive. A second locale is nearby to the southeast north of Hillsdale Road near Elan Lane, with plants inconspicuously located beneath the shrub understory. It is also reported north of Highway 94 just west of the Tecate Road turnoff at a site difficult to access. Old biological survey reports note sites on steep slopes at the Hester Granite Pit on Willow Glen Road north of Oak Drive, as well as on the eastern slopes at the mouth of Sloane Canyon. Most of the historical habitat probably utilized by this species has been extirpated by sand mining and grading for golf courses. Herbarium collections examined were for Whispering Oaks near the Sloane Ranch, and a first year burn at Cottonwood, 3 miles below Barrett. The creeks and tributaries of the upper Otay River and Sweetwater River seen to define the range of this species. A Data Base record is from the confluence of an unnamed creek and Potrero Creek approximately 0.75 mile west of Grapevine creek northeast of Tecate Peak.

No specimens for Dean's Milk Vetch are found in the San Diego Natural History Museum's herbarium from Baja California.

Status: This very rare San Diego County endemic is declining and is now endangered at most of the known sites; it should be given immediate listing as federally Endangered. No extensive extant populations are known for Dean's Milk Vetch. This species has the potential for extinction within the next two decades. All populations should be protected with substantial habitat buffers included. Horticultural requirements for growing this species need to be investigated.

Jacumba Milk Vetch [Astragalus douglasii (T. & G.) var. perstrictus (Rydb.) Munz & McBurn. ex


Copyright May 1994 Craig H. Reiser.

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