There are fifty or more common kinds of Prickly Pear, many of them as yet un-described and little known. They have flattened joints and yellow flowers, like the one illustrated, which is typical, often measuring three or four inches across, the petals variously tinted outside with salmon, rose, and brown.

There are many kinds of Cactus, round, cylindrical, or oval plants, covered with knobs, bearing clusters of spines, those of some species having hooked tips. They may be known by their smooth fruits, without scales or spines.