There are about 2,000 species of cactuses. Most species grow in hot, dry regions especially in Mexico and the Southwestern United States. But cactuses are also found in rain forests and on mountains. Some even grow in Alaska and near Antartica.
Cactuses vary widely in shape and size.
For example, the giant saguaro looks like a bare tree with a thick trunk and a long, unturned branches. Some cactuses look like pincushions,starfish, or even blades of grass. All cactuses reproduce sexually. They bear flowers with male and female parts. The male part produces a yellow powder called pollen.