July 20, 1806, along the Marias River, Montana.

Perennial shrub, numerous yellowish-white to grayish, rigid branches that are very spiny. Flowers inconspicuous, rose-colored, on ends of branches forming dense spikes to 1.5 in (3.8 cm) long. Height: to 8 ft (2.4 cm).

Flat, barren, often very alkaline areas with water close enough to soil surface for roots to get free water. Elevations of 1,000-7,000 ft (305-2,134 m) in desert as well as nondesert areas.

Continuous distribution from southern Canada to southern Nevada, northeastern Arizona, and northwestern New Mexico. Southward, scattered in California, southern Arizona, and western Texas into Mexico. Occurs as far east as North Dakota.