milkvetch
''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...
known by the common names Cushenbury milkvetch and silvery-white milkvetch.
Distribution
It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
San Bernardino County, California
San Bernardino County (), officially the County of San Bernardino, is a County (United States), county located in the Southern California, southern portion of the U.S. state of California, and is located within the Inland Empire area. As of the ...
, where it is known from the northern slopes of the
San Bernardino Mountains
The San Bernardino Mountains are a high and rugged mountain range in Southern California in the United States. Situated north and northeast of San Bernardino and spanning two California counties, the range tops out at at San Gorgonio Mountain ...
near the settlement of Cushenbury. Most of the plants are located in the woodland and scrub of the slopes between
Big Bear
Big Bear, also known as ( cr, ᒥᐢᑕᐦᐃᒪᐢᑿ; – 17 January 1888Mistahimaskwa ...
in the mountains and
Lucerne Valley
Lucerne Valley is a census-designated place (CDP) and valley landform in the southern Mojave Desert, in western San Bernardino County, California.
Geography
The geographic valley is defined by the surrounding Granite Mountains, Ord Mountains, ...
in the
Mojave Desert
The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily in ...
at the foot of the range.
It grows in habitat rich in
carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...
rock. It is a federally listed
endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...
''Astragalus albens'' is an annual or perennial herb producing a prostrate mat of delicate stems coated densely in silvery hairs. The leaves are generally a few centimeters long and made up of several gray-green oval-shaped leaflets less than a centimeter long each. The
inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
arises upright from the low patch of foliage and bears up to 14 pealike flowers. Each flower is dark-veined light to deep purple with a spot of white or light pink in the throat.
The fruit is a
legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
pod between one and two centimeters long. It is roughly hairy and crescent-shaped, drying to a thick papery texture.
Conservation
The main threat to this species is
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
mining, a large industry in this part of the San Bernardino Mountains. This form of mining alters the local habitat by physically removing plant life for
quarries
A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their environ ...
,
road construction
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
, and load dumping. It also produces major changes in the
hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...
of the area and releases large amounts of carbonate dust into the air which combines with water and forms a very thin layer of what is essentially
cement
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mix ...
over the habitat. Most of the populations of this plant are located on sites of active mining or sites which are targeted for mining in the future.
Most of these sites are part of
San Bernardino National Forest
The San Bernardino National Forest is a United States National Forest in Southern California encompassing of which are federal. The forest is made up of two main divisions, the eastern portion of the San Gabriel Mountains and the San Bernard ...
, and there are plans to set aside pieces of habitat for this and other endemics. Other threats to the species include
off-road vehicle
An off-road vehicle, sometimes referred to as an overland or adventure vehicle, is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with dee ...
use and
urban development
Urban means "related to a city". In that sense, the term may refer to:
* Urban area, geographical area distinct from rural areas
* Urban culture, the culture of towns and cities
Urban may also refer to:
General
* Urban (name), a list of people ...