A Thorny Cactus In My Garden In Burdwan, West Bengal, India Stock Photography

A Thorny Cactus in my garden in Burdwan, West Bengal, India. A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with thousands of known species of the order Caryophyllales. Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert. Cacti show many adaptations to conserve water. Almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade.