Erect clusters of white or purplish to magenta, pea-like flowers (bilaterally symmetrical) cover this sprawling plant with stems that reach 2 feet long and curve upward. Note the surfaces of the 5–15 pairs of leaflets are mostly hairless above and hairy below. The common and species names come from the distinctive fruit, a brownish-purple, plum-like pod, which distinguishes this species. The foliage is not  poisonous to livestock.

FLOWERS: March–June. Two common varieties – white flowers with a purple tinted keel, or purple, light blue, or pinkish flowers. Spike-like clusters (racemes) have  2–25 pea-like flowers on a leafless, 1–4 inch long (2.5–10 cm) stem. Flowers have 1 upright banner petal to 1-inch long (25 mm), 2 small side wing petals, and 2 fused keel petals to 3/4-inch long (20mm). Clusters of plum-like pods are purplish, smooth, spherical, 1/2–1 inch (1.2-2.5 cm) long, fleshy with 1 chamber or hollow with 2 chambers (depending on variety). The stems with pods lie prostrate on the ground.

LEAVES: Alternate. Blade 2–5 inches (3–13 cm) long, pinnately compound with 15-29 broad to narrowly-elliptic leaflets 1/8–1-inch long (3–24 mm), spaced along the midrib, hairless above, hairy below.

HABITAT: Sandy, gravelly, loam soils, roadsides; prairies, pinion-juniper woodlands.

ELEVATION: 4,300–7,600 feet.

RANGE: Widespread west of the Mississippi River through the Rocky Mountain states.

SIMILAR SPECIES: Three varieties of  A. crassicarpus occur in NM: var. crassicarpus, in ne. plains, has purplish flowers and fleshy pods with 1 chamber; var. cavus, widespread in cent. and w. NM, has white flowers and a hollow pod with 2 chambers; var. paysonii, known in NM only from Colfax Co., has purple flowers and hollow pods with 2 chambers. More than 75 Astragalus species in NM with similar pea-like flowers.

NM COUNTIES: Widespread in low- to mid-elevation, dry habitats: Bernalillo, Catron, Cibola, Colfax, Curry, Dona Ana, Eddy, Harding, Lincoln, McKinley, Otero, Quay, Roosevelt, Sandoval, San Miguel, Sierra, Socorro, Torrance, Union, Valencia.