Astragalus didymocarpus, Dwarf White Milkvetch
Scientific Name: Astragalus didymocarpus
Common Name: Dwarf White Milkvetch
Also Called: Locoweed, Miles' Milk-vetch, Rattleweed, Two Seeded Milkvetch, (Spanish: Hierba Loca (generic), Cascabelito)
Family: Fabaceae or Leguminosae Family
Size: 1 foot or more.
Growth Form: Forb/herb; stems prostrate or erect slender, strigose
Leaves: Green, alternate; pinnately compound; linear to oblanceolate.
Flower Color: White and purple or whitish with purple; fruit a legume
Flowering Season: February to April; variety "milesianus" blooms March to June in California.
Elevation: 1,000 to 2,500 feet.
Habitat Preferences: Low 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.
North America & US County Distribution Map for Astragalus didymocarpus.
U.S. Weed Information: No information available.
Invasive/Noxious Weed Information: No information available.
Wetland Indicator: No information available.
Threatened/Endangered Information: Listed by California Rare Plant Ranks (formerly CNPS Lists) 1B.2; Rare, threatened, or endangered in California and elsewhere; .2 Fairly endangered in California.
Genus Information: Several hundred species in Astragalus throughout North America; 80 or more species in Arizona.
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.