Coryphantha ramillosa is a rare species of cactus known by the common names bunched cory cactus and whiskerbush. It is native to the border region between Texas in the United States and Coahuila in Mexico. Because it was believed to be rare and threatened by a number of processes, it was federally listed as a threatened species of the United States in 1979. The cactus occurs in desert scrub habitat, generally in dry, rocky, barely accessible areas where few other plants grow. The substrate is limestone. The plant is being propagated and studied at Desert Botanical Garden in Phoenix, Arizona.