Astragalus didymocarpus

Astragalus didymocarpus is a species of milkvetch known by the common names Dwarf white milkvetch and Two-seeded milkvetch. It is native to the southwestern United States and northern Mexico, where it can be found in many types of habitat.

Description
Astragalus didymocarpus is a slender, hairy annual herb growing erect to about 30 cm tall, drooping, or flat on the ground in a spreading clump. The leaves are up to 7 to 8 cm long and are made up of narrow to oblong leaflets. The inflorescence is a cluster of up to 30 purple-tinted white flowers, each under 1 cm long. The inflorescence is covered in long black and white hairs.

The fruit is a small, spherical legume pod which dries to a stiff papery texture.

Varieties
There are several varieties of Astragalus didymocarpus:
 * A. d. var. didymocarpus - erect herb found in western Nevada and much of California
 * A. d. var. dispermus - prostrate form native to the desert regions
 * A. d. var. milesianus (Miles' milkvetch) - rare variety found only along the Central Coast of California
 * A. d. var. obispoensis - form with ascending stems native to coastal southern California and Baja California

Ecology
In the Mojave Desert, Astragalus didymocarpus is foraged on by desert tortoises (Gopherus agassizii) and is a significant part of their diet.