Floris van Breugel / Barrel cacti (Ferocactus pilosus) and Ocotillo overlook Palm oasis at sunrise, Anza-Borrego Desert State Park, California, USA March

Jack Dykinga / Cardon cactus (Pachycereus pringlei) and Biznaga/Barrel cactus (Ferocactus diguetii),growing at the edge of the sea, CONANP protected area.Catalina Island, Sea of Cortez, Baja Sur, Mexico. February 20...

Patricio Robles Gil / Barrel cactus (Ferocactus pilosus) Chihuahuan desert, Mexico

Jack Dykinga / Close-up of two Barrel cacti (Ferocactus acanthodes) in the eastern Chihuahuan Desert, Mexico

Jack Dykinga / A cluster of flowering Barrel cacti (Ferocactus stainsii) with Yuccas (Yucca sp) in the Eastern extension of the Chihuahuan Desert, Tamaulipas, Mexico

Jack Dykinga / Arizona Barrel Cactus (Ferocactus wislizenii) flower in full bloom amid the cactus spines, Saguaro NP, Arizona, USA

Jack Dykinga / Clusters of Barrel Cacti (Ferocactus stainesii) and Yuccas (Yucca sp) with the Sierra Madre in the background, Chihuahuan Desert, Mexico, Central America

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni), two flowers with bee pollinating. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering besides Prickly pear (Opuntia sp), in desert. Arizona.

Tim Fitzharris / Saguaro (Carnegiea gigantea) and barrel cacti, Santa Catalina Mountains, Arizona