Coryphantha echinus

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Coryphantha echinus is a cactus known as the sea urchin cactus, hedgehog Cory cactus, or rhinoceros cactus. It is listed as Least Concern by the IUCN. It belongs to the plant family Cactaceae and the genus Coryphantha; its full name is Coryphantha echinus (Engelm.) Britton & Rose (previously described as Mammillaria echinus). This cactus grows in the southern and eastern Trans-Pecos region, from Del Rio in Texas into Chihuahua and Coahuila in Mexico, with occasional finds in the northeast Trans-Pecos. It usually grows alone but can form small clusters. It produces short-lived yellow flowers that last only a few hours, typically from April to July, followed by green fruits. It was first collected in 1849 by Charles Wright and was described as Mammillaria echinus by George Engelmann before being reclassified as Coryphantha echinus by Britton & Rose.