Claret Cup Cactus

You will find Claret Cup cacti at the elevations between 4000 - 9000 feet in the Mojave Desert. They grow up to 6 inches in height and often form crowded clumps like the one in my photo. However it is not uncommon to see a singular barrel shaped claret cup cactus.
They are the first species of cacti to bloom in spring and their crimson red flowers remain open throughout the night.
Photographed in Red Rocks, Nevada.