Cactus plants come in many shapes and sizes, have sharp spines, and showy flowers. They are found around the world but are native to the Americas. Some cacti may look like a pincushion; others a cow’s tongue or a beaver’s tail and some like a shrub or small tree. With nearly 2000 species of cacti in the world, a variety of shapes and appearances can be found.
All cacti are succulents, most are stem succulents; represented by thick fleshy stems with little or no woody tissue. The sharp spines are believed to have evolved from the now missing leaves of the cactus. Summer time is when cacti are actively growing and able to absorb water from the warm soil. During the winter months they remain dormant because of their inability to take in water from the cold ground.
The best habitats for most cacti are in hot, dry regions such as the desert southwest portion of the United States. However some cacti also thrive in mountains, rainforests, and even arctic regions.
The spines of a cactus can vary in size and shape. Some spines are long and rigid while others may resemble a fishhook. The spines grow from areoles (modified branches) in clusters, and prevent the plant from being eaten by animals.
All cacti produce flowers. Colors can range from white to yellow to red and may bloom for only a short time, some less than one day. The flower also originates from the areoles, and the bright blossoms attract birds, bats, and insects to pollinate them. Once pollinated, the cactus will produce a fruit filled with seeds, which can then be eaten and scattered by birds and other animals.
The root system of a cactus remains very close to the surface of the soil, where it can collect as much water as possible during periods of precipitation. They may also have very long roots which quickly absorb water and transport it to the fleshy stem for storage.
Although all cacti are succulents, not all succulents are cacti. Some people, new to the Desert Southwest, mistake succulent plants for cacti. Succulents that are not cacti include: agave, yucca, and ocotillo.
Zion National Park is home to number of different cactus species, including claret cup, pricklypear, and cholla.