About Pediocactus nigrispinus (Hochstätter) Hochstätter
Pediocactus nigrispinus is initially spherical when young. As it matures, it becomes densely spiny, usually with a flattened ovoid or egg-shaped form. Mature plants reach 25 centimetres (10 in) in height, and 5 to 15 centimetres (2 to 6 in) in width. This cactus typically grows as a cluster of ribbed stems, each 7.5–12.5 centimetres (3–5 in) wide, with green to grayish-blue coloration. It has a characteristic dense spine arrangement: 4 to 11 large central spines, 1.5 to 2.5 centimetres (1⁄2 to 1 in) long, with a yellowish to reddish-brown color. It also bears 15–35 smaller whitish spines that reach up to 1.5 centimetres long. Its showy pink to magenta flowers bloom in spring, growing in a cluster near the apex of each stem.
This species, also called the Columbia Plateau cactus, grows in big sagebrush and lower montane dry habitats across dry regions, steppes and semi-deserts of eastern Washington, Oregon, and extending into Idaho. It is found on hills or rocky outcrops, at altitudes between 260 and 1,200 metres (850 and 3,940 ft). It occurs in scattered locations but is often abundant where it grows. Associated plant species in its habitat include Opuntia polyacantha and Opuntia fragilis.
