Search / Plant Profile / Astragalus brauntonii

Plant Profile

Braunton's Milkvetch (Astragalus brauntonii)

This shot shows the plant in detail, featuring the leaves and flowers. Photo Credit: Bart O'Brien

Global Rank: G2 - Imperiled
Legal Status: Federally Endangered
Family: Fabaceae
State: CA
Nature Serve ID: 156760
Lifeform: Forb/herb
Date Inducted in National Collection: 03/05/1993

Description:

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).

Where is Braunton's Milkvetch (Astragalus brauntonii) located in the wild?

Habitat:

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).

Distribution:

Braunton's milkvetch is known to occur only in the hills bordering the Los Angeles basin in southern California, from Ventura, Los Angeles, and Orange counties. Known occurrences of this species are

States & Provinces:

Braunton's Milkvetch can be found in California

Which CPC Partners conserve Braunton's Milkvetch (Astragalus brauntonii)?

California Botanic Garden

Not Sponsored

Conservation Actions

Assigned 06/09/17

Santa Barbara Botanic Garden

Not Sponsored

Conservation Actions

Assigned 06/13/17

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

09/01/2020

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 14 accessions of Astragalus brauntonii in orthodox seed collection. There are as many as 961453 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

09/01/2020

Based on an September 2020 extract of the California Plant Rescue Database, Santa Barbara Botanic Garden holds 1 accessions of Astragalus brauntonii in orthodox seed collection. There are as many as 100 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

08/25/2020

Rancho Santa Ana Botanic Garden has undertaken preliminary germination and growth experiments for possible introduction efforts (Hannon pers. comm.)

08/25/2020

USFWS section 6 funding was provided for a 1998 study of the ecology and distribution of Braunton's milkvetch, in particular soil seed bank characteristics and pollination requirements (USFWS 1999).

08/25/2020

Currently, the southern California National Forests are developing suitable habitat models for this species to identify areas on National Forest System Lands that could potentially support additional occurrences of Braunton's milkvetch and to determine whether this taxon is present or absent within these areas and if present, manage populations accordingly.

08/05/2020

Based on an August 2020 extract of the California Plant Rescue Database, Santa Barbara Botanic Garden has collected 1 seed accessions of Astragalus brauntonii from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 18 maternal plants

08/05/2020

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 6 seed accessions of Astragalus brauntonii from 2 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 6 maternal plants

Nature Serve Biotics

05/02/2017

Endemic to the mountains surrounding the Los Angeles basin, California, where it is currently known from 4 general areas. Currently, fewer than 100 individual plants are known, but the species' seed bank could generate larger populations if appropriate fire events occurred. The species may be restricted to limestone, which is a rare substrate within the limits of its known distribution. A. brauntonii is threatened by urban development and habitat fragmentation, and by the resultant alteration of natural fire cycles. The fact that the plants are only visible for 2-3 years following a fire or other disturbance (which may occur only once in 20-50+ years) may make the populations especially vulnerable to destruction.

Valerie Soza

01/01/2010

The major threat to this species is immediate loss of native habitat. Most of the habitat is on private lands or in the immediate vicinity of areas of expanding urban development, including construction of housing, golf courses and infrastructure. In

Valerie Soza

01/01/2010

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.

Valerie Soza

01/01/2010

USFWS section 6 funding was provided for a 1998 study of the ecology and distribution of Braunton's milkvetch, in particular soil seed bank characteristics and pollination requirements (USFWS 1999). In addition, Rancho Santa Ana Botanic Garden has undertaken preliminary germination and growth experiments for possible introduction efforts (Hannon pers. comm.)

Valerie Soza

01/01/2010

Valerie Soza

01/01/2010

More surveys are needed in suitable habitat post-fire or after some other disturbance to locate additional populations of Braunton's milkvetch. Seeds remain in the soil bank for many years before germinating and therefore, other areas that have not burned in many years could potentially support additional occurrences of this plant. Fire suppression regimes need to be reevaluated in areas of suitable habitat. In the meantime, suitable habitat should be secured and then burned periodically to stimulate germination of potential seed (Skinner 1991).

Valerie Soza

01/01/2010

Because Braunton's milkvetch seed remains dormant in the soil bank for many years, there is more likely to be a higher amount of genetic diversity in the seed bank than in living plant populations. Seed should be collected from newly-discovered populations and stored at established conservation seed programs. Existing populations should be monitored annually and seed should also be collected from newly-established individuals to increase the genetic diversity and gene pool for this species stored at conservation seed programs.