Slightly less common that Opuntia basilaris is Opuntia polyacantha var. erinacea, also known as Old Man Cactus or Grizzlybear Pricklypear. Unlike O. basilaris, this plant has much more of the typical cactus appearance, with multiple long spines projecting from its areoles. At a distance, this dense "foliage" gives the plant a grizzled, white appearance, hence the common name.
The flowers are typically orange to yellow in color, emerging early to mid summer.