Engelmann & Bigelow, Proceedings of the American Academy of Arts and Sciences 3: 291, 1856
Following the example of Ferguson (1988), we treat Opuntia chlorotica chlorotica as a species with three varieties: chlorotica, santa-rita, and gosseliniana. O. chlorotica chlorotica summons up visions of gunfights and posses. The Flora of North America online provides a technical description of this O. chlorotica variety. Plants may reach 6(7)-ft tall and usually from a single trunk that can reach 1 ft in diameter. Plants are often upright, but some spreading may occur. Cladodes are suborbicular or orbicular and may be about 8(9) inches across all diameters. Spines (1- to 1.5-inches long) are yellow and glochids can become prominent and robust on older pads, up to 3/4 inch long. The trunk is spiny. Though most plants are spiny, some populations have plants that are almost spineless. There may be 1 to 6 spines per areole that often bend back towards the cladode surface. See the original description. The fruit pulp is often colorless and without flavor. O. chlorotica is diploid.
An early photograph of O. chlorotica chlorotica (Bulletin of the Torrey Botanical Club, 1916) shows that this plant is distinctive. O. chlorotica chlorotica has spines on the trunk and pancake-like cladodes. Flowers are modest, about 2 inches across, and fruit is semi-spherical or egg shaped. O. chlorotica chlorotica is closely related to O. chlorotica gosseliniana and O. chlorotica santa-rita.
The plant is found in NV, CA, much of AZ, and perhaps barely into southwestern UT. It is also found in the extreme southwest of NM. Typically, O. chlorotica chlorotica grows in well-drained, rocky soils, sometimes between boulders or on cliff faces. However, it may grow in sandy soils. Britton and Rose reported that the species has a wide distribution but is primarily confined to mountain canyons and is only rarely found on mesas or flat soils.