Sclerocactus polyancistrus is a species of cactus known by several common names, including redspined fishhook cactus, Mojave fishhook cactus, pineapple cactus, and hermit cactus.
Sclerocactus polyancistrus is native to the Mojave Desert in eastern California and southern Nevada. It grows in desert scrub, woodlands, and canyons, often on limestone substrate.
The Sclerocactus polyancistrus cactus has a cylindrical stem up to 25 centimeters tall by 8 wide. They may grow in clusters. The cactus is densely spiny, each areole has several reddish or white central spines with hooked tips and several more white spines around the edge.
The fragrant flower is up to 10 centimeters wide and may be most any shade of pink or red-violet. The scaly, fleshy fruit is 2 or 3 centimeters long.