The following Participating Institutions are custodians for this species in the CPC National Collection:
Rancho Santa Ana Botanic Garden
Santa Barbara Botanic Garden
The conservation of Astragalus brauntonii is fully sponsored.
Valerie Soza contributed to this Plant Profile.
This is an ephemeral perennial member of the pea family that reaches a height of 15 dm with dull lilac flowers blooming March-July (Munz 1974). It typically appears following a chaparral fire or other form of mechanical disturbance and persists several years before senescing or becoming crowded out by developing vegetation (Skinner 1991). Braunton's milkvetch seeds persist in the soil bank for many years and have a seed coat that is typical of many chaparral plants and adapted to germinate after some form of disturbance which breaks seed dormancy (USFWS 1999).
Distribution & Occurrence
Braunton's milkvetch generally occurs below 2100 feet (640 m) in elevation, on south-, west-, and east-facing slopes, in open areas within chaparral. It is often found growing in disturbed areas such as burn areas, along fire roads or fuel breaks, and in areas that have been cleared by some means and where competition is low. This plant was historically found in gravelly clay soils overlaying granite sandstone, but is now found often associated with carbonate soils derived from scattered limestone lenses, or on noncarbonates at down-wash sites (Skinner 1991; USFWS 1999).
|There are 16 known extant occurrences of Braunton's milkvetch, with 12 historical occurrences that have been extirpated of presumed extirpated (CNDDB 2001). Braunton's milkvetch is currently known from four general areas in Ventura, Los Angeles, and Orange counties: eastern end of Simi Hills, eastern half of the Santa Monica Mountains, southern base of the San Gabriel Mountains, and northwestern side of the Santa Ana Mountains.|
Bees: Digger bees2, Bumble bees2,3 (Bombus3), Honey bees2, Anthidium3, Anthocopa3, Hoplitis3
Bees: Bumble bees4(Bombus mixtus4, Bombus sitkensis4, Bombus vosnesenskii), Solitary bees4(Osmia dolerosa4, Osmia laeta4, Osmia tristella4)
Flies:Hover flies4 (Bombilius major4), Syrphid flies4
Conservation, Ecology & Research
Skinner, M. 1991. Rare plants of California: Braunton's milkvetch. Fremontia. 19, 3: 6-7.
USFWS. 1997. Determination of endangered status for two plants and threatened status for four plants from southern California. Federal Register. 62, 19: 4172-4183.