Cactus (Cactaceae)

Cactus have many different shapes. They are found around the world. There are about 2,000 different kinds of cactuses.

Characteristics: Most cactus have fleshy stems. They do not have wood like trees. They never have leaves. Cactus have spines. They grow in summer.

Size: Cactuses have many sizes and shapes. They can be very tall or very small.

Desert Garden

Where Do They Grow? Most cactus grow in hot, dry places. They are common in Mexico and the Southwestern United States.

Arizona Barrel Cactus
Barrel Cactus Fruit
California Barrel Cactus
Parts of a Cactus: Cactus can live in hot, dry places. The stem stores water. The firm skin holds in water.

Cactus spines keep the plant safe. Spines can be short, long, soft, or sharp.

Spines can be straight or hooked.

They sometimes grow in rows and patterns.

Some cactuses have ribs. The ribs give shade to part of the plant.


Engelmann's Prickly Pear

All cactuses make flowers.

Flowers can be white. Or, they can be a bright color such as yellow, orange, red, or purple. The flowers only last a few days.

Claret Cup Hedgehog

Cactuses grow in sandy, rocky soil.

They have very long roots. The roots drink up rain water.

Beavertail Prickly Pear

Life Cycle: Flowers, fruit, and seeds help the cactus multiply. Only one or two seeds will live to make a new cactus.

Some cactuses have stems that break. The stem falls to the ground. The stems grows in the soil and start a new plant.

Most cactuses grow very slowly. They can live 50 to 200 years.

Organ Pipe

Kinds of Cactuses: Some of the common cactuses in the southwest US include the barrel, prickly pear, organ pipe, cholla, barrel, and saguaro cactuses.

Saguaro, organ pipe, and barrel cactuses are in the same family. The saguaro (left) has many branches that look like arms. Saguaro are very tall. They can live for 200 years. Birds live in this cactus.

The organ pipe cactus (above) has many tall stems and thin arms. They are less common.


The barrel cactus looks round. It is very common. They can be big or small.

All barrel cactus have ribs. They have firm spines. The fruit on top of the plant are juicy, but taste bad.

Chollas and prickly pears are in the same family.

Stems of the jumping cholla fall to the ground. Some people say they 'jump' on people as they walk by.

Teddy bear cholla look soft, but have sharp spines. They stick to skin and are hard to get out.

Desert packrats make their dens with cholla. Some of these nests are hundreds of years old. They are dirty, so don't touch them.

Teddy Bear Cholla

Prickly pears have many flat pads. They look like pancakes. They have large and small spines.

The fruits of prickly pear are juicy. Some people eat them as a vegetable.

Santa Rita Prickly Pear

Value of Cactuses: Cactuses are important to animals and people. Small animals, insects, and birds eat their stems and flowers.

Birds and animals hide and live in cactus.

People eat cactus fruits.

Cane Cholla Fruit
People grow and sell cactus plants. It is illegal in some places to dig up cactus. Some cactus like saguaro are in danger. National parks save them.

Mistaken for Cacti: Some plants look like cactus, but are not cactus. 'Not-cactus' plants include Century plants, hen-and-chicks, yuccas, sotol, bear grass, desert pi

Cholla Wood

More Information

Note: All photographs taken with a digital camera in Arizona, New Mexico, Utah, and Texas.
Developed by Annette Lamb and Larry Johnson, 05/02.