About Astragalus nuttallianus DC.
Astragalus nuttallianus DC. is a milkvetch species with the common names smallflower milkvetch and turkeypeas. It is native to the southwestern and south-central United States and northern Mexico, and occurs in many habitat types, most often in dry areas. This is an annual herb with a variable appearance, particularly across its different varieties. It grows slender, hairy stems that reach between 4 and 45 centimeters in length. Its leaves are up to 6.5 centimeters long and are composed of multiple oval-shaped leaflets that may have pointed or rounded tips. The inflorescence holds 1 to 4 white, purple, or bicolored flowers, each less than one centimeter in length. The fruit is a legume pod measuring 12 to 26 millimeters long. Several varieties of this species are recognized: A. n. var. austrinus is distributed from California to Oklahoma to northwestern Mexico; A. n. var. cedrosensis is native to the Sonoran Desert; A. n. var. imperfectus is native to the southwestern United States; A. n. var. macilentus is native to New Mexico and Texas; A. n. var. micranthiformis occurs in the southwestern United States; A. n. var. nuttallianus is found in the central United States from Kansas to Louisiana; A. n. var. trichocarpus is native to Texas and Oklahoma; A. n. var. zapatanus is a Texas endemic.
