is easily recognized by its purple pads, a color that becomes more pronounced after long periods without rainfall. The species tends to have dark (sometimes light) spines that grow preferentially from the top of the pads, but it is prone to hybridization, giving rise to a more uniform covering of spines, and less even purple coloration. Occasionally spines are absent, and when present are quite variable in both number (1 to 15) and length (1 to 4 inches).
Flowers are yellow with a red center, and appear in late spring, while the fruits are purple, an inch or more long. The plant spreads sideways more than upwards, and does not develop a central trunk; new pads readily take root, so the clump never becomes more than 3 feet high.