Vickie White, age 11, of McAllen, Tex., for her question:

ARE THERE MANY DIFFERENT KINDS OF CACTUSES?

More than 1,000 different kinds of known cactuses can be found on earth, and most of this large family of plants live in North America. A great abundance of the plants grow in Mexico and in the southwestern states of the United States.
Cactuses grow where the land is dry. The plants are well suited to places with very little rainfall.
In most other plants, the food for the plant is made in the leaves, and the leaves give off water. In the cactus, most of the leaves have disappeared so that the plant may better hold its moisture. Cactus stems have taken over the job of making food for the plant.
Cactus stems can actually store water. One variety, the barrel cactus, is able to store large amounts of water in the pulp of its upper portion. Indians that lived in the Southwest, by the way, used the tough, curved spines of the barrel cactus as fishhooks.
Most cactus plants, as a matter of fact, are protected by sharp bristles and spines. The spines help protect the plant against animals that live in the desert. Were it not for these spines, the cactus plants would be eaten and die out.
The spines grow from parts of the plant called areoles, which look like tiny cushions. The areoles are arranged in definite patterns over the surface of the plants. The new branches and beautiful flowers of the cactus also grow, like the spines, from the areoles of the plant.
The roots of the cactus plant are covered with a corklike bark and lie close to the surface. They spread far out so they can catch the water from light rains and quick floods that may take place in desert areas. A cactus plant only three feet tall may have roots over 10 feet long.
Cactuses come in all shapes and sizes. Some plants grow like vines with roots that are exposed to the air. Others grow as large as trees.
Largest cactus found in the United States is the saguaro or giant cactus. It grows in forests or scattered groups in the lands that drain into the Gulf of California. Indians of Arizona use the dried woody ribs of the saguaro stems for fuel and for making frames for their homes. The fruits of this cactus ripen in June and July and the Indians eat these fruits fresh or as preserves.
Many beautiful cactus plants are members of the cereus group. These include night blooming cereus, whose large fragrant flowers open only at night.
One kind of cactus is called the old man cactus. It is covered with long, white hairs and is often grown in indoor cactus planters.
The peyote grows in northern Mexico and southern Texas. This small cactus contains a powerful drug that is used by certain Indians in religious rites.
The people of Mexico find uses for the many kinds of cactuses that grow in their country. The joints of a flatleaved cactus called opuntia are eaten boiled or fried. The flowers can be made into salads. The juicy fruits of this kind of cactus are eaten raw or cooked. Then the seeds of many different kinds of cactus are ground up into a meal and made into cakes.