Hedgehog Cactus (Echinocereus)

I don't know what species of hedgehog cactus this is but it does appear to be in the genus Echinocereus. This photograph was taken in the Sonoran Desert near Tucson. Hedgehog cacti are small and spiny (like a hedgehog) and they grow in low clumps. It is thought that the clumping, low colonies of hedgehog cacti can grow at higher elevations, up to 7,000 feet, because less surface area is exposed to the cold. Like most cacti the fruit are edible.