Jack Dykinga / Teddybear Cholla cacti (Cylindropuntia bigelovii) in sunset light, Kofa National Wildlife Refuge, Arizona, USA

Rolf Nussbaumer / Teddy Bear Cholla Cactus (Cylindropuntia bigelovii) in field of Mexican Gold Poppy (Eschscholzia californica mexicana), Tonto National Forest, Bartlett Lake , Arizona, USA, March

Rolf Nussbaumer / Teddy Bear Cholla Cactus (Cylindropuntia bigelovii) in field of Mexican Gold Poppy (Eschscholzia californica mexicana), Tonto National Forest, Bartlett Lake, Arizona, USA, March

Philippe Clement / Loose joints of the Teddybear Cholla {Opuntia / Cylindropuntia bigelovii} drop readily and attach easily to passing animals, Organ Pipe National Monument, Arizona, USA

Philippe Clement / Teddybear Cholla {Opuntia / Cylindropuntia bigelovii}, Organ Pipe National Monument, Arizona, USA

Philippe Clement / Teddybear Cholla {Opuntia / Cylindropuntia bigelovii} in front of the Ajo Mountain Range, Organ Pipe National Monument, Arizona, USA May 2007

Barry Mansell / Teddybear cholla cactus {Cylindropuntia bigelovii} Arizona desert, USA

Claudio Contreras / Teddy-bear cholla (Cylindropuntia bigelovii) at sunrise, El Pinacate Biosphere Reserve, Sonoran desert, Mexico.

Claudio Contreras / Ocotillo (Fouquieria splendens), Teddy-bear cholla (Cylindropuntia bigelovii) and Saguaro cactus (Carnegiea gigantea) in volcanic ash field, El Pinacate Biosphere Reserve, Sonoran desert, Mexico.

Claudio Contreras / Teddy-bear cholla (Cylindropuntia bigelovii) at dawn, El Pinacate Biosphere Reserve, Sonoran desert, Mexico.

Jack Dykinga / Teddy bear cholla cacti (Opuntia bigelovii) and Saguaro cacti (Carnegiea gigantea) surrounded by flowering Scorpoinweed (Phacelia crenulata) at dawn, Sonoran Desert National Monument, Arizona, USA. Ma...

Jack Dykinga / Teddy bear cholla cacti (Opuntia bigelovii) surrounded by flowering Scorpionweeds (Phacelia crenulata) and Saguaro cacti (Carnegiea gigantea) under gathering clouds in afternoon light, Sonoran Desert...