Coryphantha echinus

{{Short description|Species of cactus}}

{{Speciesbox

| image = The botanical works of the late George Engelmann, collected for Henry Shaw, esq (Pl 11) BHL31876628.jpg

| image_caption =

| status = LC

| status_system = IUCN3.1

| genus = Coryphantha

| species = echinus

| authority = (Engelm.) Britton & Rose{{Cite web|url=https://www.wildflower.org/plants/result.php?id_plant=COEC|title=Coryphantha echinus|website=Lady Bird Johnson Wildflower Center - The University of Texas at Austin|access-date=2018-06-15}}|

| synonyms = Mammillaria echinus Engelm.

}}

Coryphantha echinus is a species of cactus known by the common names of sea urchin cactus, hedgehog Cory cactus or rhinoceros cactus.{{Cite web|url=https://plants.usda.gov/core/profile?symbol=COEC|title=Plants Profile for Coryphantha echinus (rhinoceros cactus)|website=USDA|access-date=2018-06-15}} C. echinus is found in the south and east portion of the Trans-Pecos to Del Rio, Chihuahua, Coahuila and sporadically in the northeast Trans-Pecos.{{Cite book|title=Little Big Bend : Common, Uncommon, and Rare Plants of Big Bend National Park|last=Morey|first=Roy|date=2008|publisher=Texas Tech University Press|isbn=9780896726130|location=Lubbock|pages=46|oclc=80359503}} The plant normally occurs in solitary groupings, but sometimes grows as a clump.{{Cite journal|title=Coryphantha echinus: Terry, M., Heil, K., Corral-Díaz, R., Dicht, R.F. & Lüthy, A.D.|date=2009-11-18|doi=10.2305/iucn.uk.2017-3.rlts.t152140a121460549.en|doi-access=free}} It produces short-lived yellow flowers that last for a couple of hours between April and July. After flowering, it produces green fruits.

Coryphantha echinus was first collected by Charles Wright in 1849 and was later described as Mammillaria echinus by George Engelmann.