Carnegiea is a genus of cacti native to the deserts of North America, particularly found in the southwestern United States and Mexico. The most well-known species within this genus is the saguaro cactus (Carnegiea gigantea), which can grow to be quite large, reaching heights of up to 40 feet. These cacti are characterized by their tall, columnar shape and distinctive arms that extend upward. Carnegiea cacti thrive in arid environments and are adapted to conserve water. They have a thick, waxy skin that reduces moisture loss and spines that provide shade and protection from herbivores. These cacti play a crucial role in their ecosystem, providing habitat and food for various desert wildlife.