Stamps with the theme Cacti

A cactus is a plant mostly found in habitats which are subject to drought. Many grow in extremely dry environments, and are even found in the Atacama Desert, one of the driest places in the World. Cactus employ many methods to conserve water. Most species of cactus have no leaves, just spines, useful as a defence against herbivores. The spines reduce air flow close to the cactus and provide some shade, both of which help to prevent water loss. Cactus stems also store water. Some cactus produce flowers and fruit. Certain types are used as ornamental plants, others are grown for their fruit.