Shattil & Rozinski / Nature Conservancy's Southmost Preserve, Lower Rio Grande Valley at sunset, Texas, USA

Shattil & Rozinski / Santa Ana National Wildlife Refuge, Rio Grande Valley, Texas, USA

John Cancalosi / Saguaro cactus (Carnegiea gigantea), Sonoran Desert Arizona USA

Bernard Castelein / Heather (Calluna vulgaris) in sand dunes. Kalmthoutse Heide, Belgium, Europe