Identifying characteristics of cactuses can be easy if you do a bit of research.
Cactuses have a unique look and shape that has come from years of adapting to hot and dry weather conditions. Most cactuses are distinguished by a long and fleshy or succulent stem. One of the biggest characteristics are the spines that have grown instead of leaves. Some species of cactus grow flowers and even fruit.
Cactuses grow very slowly. Some species of cactus can live up to 200 years. Cactuses come in a variety of shapes and sizes. The most common is the Saquaro cactus which grows tall and has several arm-like branches protruding from the main stem. The Organ Pipe cactus has tall stems that grow in groups like an organ pipe. The Barrel cactus looks like a small round barrel, they can grow up to ten feet tall. Prickly Pears grow in a large group of small, flat branches called pads. The Prickly Pear cactus grows a delicious fruit, and in some places the pads are gathered and cooked as a vegetable. There are many other types and sizes of cactus, all with the distinguishing characteristics of tall stems and prickly spines.
Most cactuses grow in hot and dry climates. They are able to survive in very arrid conditions, growing in the sandy and rocky soil. Their roots are very long and grow close to the surface to help gather water and move it to the plant stem. They are common in Mexico and southwestern states such as New Mexico, Arizona, Nevada, Utah and California. They are able to live in such areas because of the ability to store water in the stems. The soft skin of the cactus helps retain the water and the spines help gather the water and moisture to the stem.
The spines on a cactus can be soft or hard, straight or hooked. The spines help gather water and provide shade and protection to the plant. All cactuses have flowers. The flowers only last a few days, but help in gathering moisture and propigating more cactuses. The flowers are usually white, but some species of cactus have purple, orange, red or yellow flowers.