Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Astragalus didymocarpus, Dwarf White Milkvetch

Astragalus didymocarpus, Dwarf White Milkvetch, Southwest Desert Flora Astragalus didymocarpus, Dwarf White Milkvetch, Southwest Desert Flora

Scientific Name: Astragalus didymocarpus
Common Name: Dwarf White Milkvetch

Also Called: Locoweed, Miles' Milk-vetch, Rattleweed, Two Seeded Milkvetch, (Spanish: Hierba Loca, Cascabelito)

Family: Fabaceae or Leguminosae Family

Synonyms: ()

Status: Native

Duration: Annual

Size: 1 foot (30 cm) or more.

Growth Form: Dwarf White Milkvetch is a slender, grayish forb/herb with multiple branches; stems are low lying (prostrate) and spreading; the plants are covered with short fine grayish hairs (pubescence).

Leaves: Dwarf White Milkvetch has green leaves which are are pinnately compound; the shape of the leaflets is variable.

Flower Color: Dwarf White Milkvetch has white and purple or whitish with purple; the fruit is a small round pod becoming papery as it dries.

Flowering Season: February to April; variety "milesianus" blooms March to June in California.

Elevation: 1,000 to 2,500 feet (305 - 762 m).

Habitat Preferences: Lower desert areas, open rocky areas, gravelly or sandy soil.

Recorded Range: Somewhat rare in the United States where it is native to AZ, CA and NV. It is also native to Baja California. In Arizona it occurs in northern Mojave, Maricopa, Pinal and Pima Counties; in California it is found throughout most of the southern part of the state and in Nevada it occurs in the central and southern parts of the state.

North America & US County Distribution Map for Astragalus didymocarpus.

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown
Wetland Indicator: Unknown

Threatened/Endangered Information: The variety Astragalus didymocarpus var. milesianus, Miles' Milk-vetch is listed by the California Native Plant Society as "Rare or Endangered" and the plants are "Threatened by development".

Genus Information: In North America, USDA Plants Database lists 692 species for Astragalus. Worldwide, World Flora Online includes 3,065 accepted species names for the genus.

The genus was published in 1753 by Carl Linnaeus, (1707-1778).

In the Southwestern United States: Arizona has 160 species of Astragalus, California has 180 species, Nevada has 189 species, New Mexico has 139 species, Texas has 60 species, Utah has 205 species. Data approximate, subject to revision.

4 varieties in Astragalus didymocarpus:
Astragalus didymocarpus var. didymocarpus, Dwarf White Milkvetch, (CA, NV);
Astragalus didymocarpus var. dispermus, Dwarf White Milkvetch, (AZ, CA, NV);
Astragalus didymocarpus var. milesianus, Miles' Milk-vetch, (CA only);
Astragalus didymocarpus var. obispoensis, San Obispo Milkvetch, (CA only).

Comments: Dwarf White Milkvetch is an inconspicuous plant found in lower Sonoran Desert elevations. The type specimen Astragalus didymocarpus var. dispermus was collected by Palmer in 1876 from Wickenburg, Maricopa Co., AZ.

Also see in Southwest Desert Flora; Arizona Milkvetch, Astragalus arizonicus and Ashen Milkvetch, Astragalus tephrodes.

Importance to Wildlife, Birds and Livestock
Dwarf White Milkvetch, Astragalus didymocarpus has attractive flowers, the flowers and their seeds may be visited by hummingbirds and/or small mammals including rodents and granivorous birds in search of nectar or food.

Dwarf White Milkvetch, Astragalus didymocarpus has attractive flowers, the flowers and their plants may be visited by butterflies, moths, flies, honeybees, Native Bees and other insects in search of food and nectar.

The genus “Astragalus” (Astrag'alus:) is from the Greek word "astragalos" meaning "ankle bone"; the reference is from the shape of the seeds.

The genus Astragalus was published in 1753 by Carl Linnaeus, (1707-1778).

The species epithet didymocarpus (didymocar'pus:) means with the fruit in pairs.

Ethnobotany - Native American Ethnobotany; University of Michigan - Dearborn
The genus Astragalus is known for its medicinal purposes for respiratory illnesses such as colds and coughs.

Date Profile Completed: 08/05/2015, updated 01/13/2022
References and additional information:
Kearney, Thomas H., Peebles, Robert H., 1960, Arizona Flora, University of California Press, Berkley and Los Angeles, California.
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed 01/11/2022.
World Flora Online; A Project of the World Flora Online Consortium; An Online Flora of All Known Plants - (accessed 01/11/2022)
Native Plant Information Network, NPIN. Published on the Internet; accessed 01/13/2022. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
Martin F. Wojciechowski & Richard Spellenberg 2012, Astragalus didymocarpus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on January 13, 2022.
Wikipedia contributors. "Astragalus didymocarpus." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 11 Mar. 2021. Web. 13 Jan. 2022.
SEINet for synonyms, scientific names and recorded geographic locations,
California Native Plant Society, Rare Plant Program. 2022. Inventory of Rare and Endangered Plants of California (online edition, v9-01 1.0). [accessed 13 January 2022].
Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 01/11/2022)
IPNI (2020). International Plant Names Index. Published on the Internet, The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. [Retrieved 11 January 2022].