Rolf Nussbaumer / Golden-fronted Woodpecker (Melanerpes aurifrons), male perched on Texas Prickly Pear Cactus (Opuntia engelmanni). Laredo, Webb County, South Texas, USA, April.

Floris van Breugel / Cholla cactus (Opuntia) backlit by setting sun, Anza Borrego State Park. California, USA. April 2009.

Rolf Nussbaumer / Single White Prickly Poppy (Argemone albiflora) flower, in wildflower meadow, Fennessey Ranch, Refugio, Coastal Bend, Texas Coast, USA

Rolf Nussbaumer / White Prickly Poppy (Argemone albiflora) flowering in wildflower meadow, Fennessey Ranch, Refugio, Coastal Bend, Texas Coast, USA

Edwin Giesbers / Sea holly (Eryngium maritimum) growing in sand dune, Menorca, Balearic Islands, Spain, Europe

Suzi Eszterhas / Digger Bee (Melissodes sp) pollinating Engelmann Prickly Pear (Opuntia engelmannii) flower, Red Corral Ranch, Texas

Jack Dykinga / Dense stands of Prickly pear cactus (Opuntia sp) in Tamaulipas, Mexico

Jack Dykinga / Gopher snake (Pituophis sp) amongst Lechuguilla (Agave lechuguilla) and prickly pear cacti (Opuntia macrocentra), Maderas del Carmen Natural Reserve, Mexico

Rolf Nussbaumer / Daring Jumping Spider {Phidippus audax} adult on fruit of Texas Prickly Pear Cactus (Opuntia lindheimeri) Rio Grande Valley, Texas, USA, June

Jack Dykinga / Close-up of Agave (Agave montana) with red thorns / spines and interesting patternation on blades, Sierra Madre Oriental mountain range, Tamaulipas, Mexico

Tim Fitzharris / Opuntia (Opuntia sp) in Chihuahuan Desert landscape, Big Bend National Park, Texas

Rolf Nussbaumer / Big Bend NP, Chihuahuan desert, Texas, USA. Strawberry cactus + Prickly pear cactus.