Kinds of Cactus Stems

Columnar Stems

• Some of the most familiar types of cacti are those that grow thick columnar stems. These cacti range from small, globe-shaped plants to the towering saguaro, whose branching stems can tower over 30 feet high. Columnar cacti can be formidably spined, as with many of the barrel cacti, or nearly spineless, as with the Easter lily cactus, which grows a columnar stem up to 8 feet tall. These kinds of cactus stems feature both deep ribbing or almost smooth surfaces, and every variation in between.

Pad-Like Stems

• Cacti such as the prickly pear grow segmented stems made up of wide, flat pads. These fleshy lobes are covered with small bumps that sprout clusters of spines, both large straight spines and smaller, barbed spines called glochids. Both the pads of the prickly pear and the fruits that develop on them are edible and are often sold in grocery stores.

Segmented Stems

• Although they are members of the genus Opuntia, just like prickly pear cacti, cholla cacti have a strikingly different kind of stem. The stems of cholla are jointed like prickly pears, but their segments are cylindrical, and they often branch out in a tree-like manner. Cholla stems are also covered with small, barbed glochids, and the segments of some varieties detach easily from the plant, allowing them to cling painfully to passing people or animals.

Leaf-Like Stems

• The stems of the Christmas cactus are also segmented, but they are flat and leaf-like, with serrated edges but no spines. The stems grow in a chain formation and have an arching, often drooping habit. In nature, Christmas cacti are epiphytic, meaning that they live on the trunks and branches of trees rather than in soil. New plants are propagated in nurseries and at home by breaking off a segment of stem and rooting it in a planting medium.