About Coryphantha echinus (Engelm.) Britton & Rose
Coryphantha echinus (Engelm.) Britton & Rose is a species of cactus with three common names: sea urchin cactus, hedgehog Cory cactus, and rhinoceros cactus. This cactus is distributed across the southern and eastern parts of the Trans-Pecos region extending to Del Rio, the Mexican states of Chihuahua and Coahuila, and occurs sporadically in northeastern Trans-Pecos. It most often grows alone in solitary groupings, though it occasionally forms clumps. It produces short-lived yellow flowers that only last a few hours, blooming between April and July. After flowering finishes, it develops green fruits. First collected by Charles Wright in 1849, Coryphantha echinus was initially described as Mammillaria echinus by George Engelmann.
