Engelmann & Bigelow, Proceedings of the American Academy of Arts and Sciences 3: 291, 1856
Holotype; Lectotype; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Drawing (Botany of the Expedition, 1856, plate VI)
What is Opuntia chlorotica chlorotica?
O. chlorotica chlorotica is the prickly pear cactus that summons up visions of gunfights and posses. It is one of three varieties: chlorotica, santa-rita, and gosseliniana within the O. chlorotica complex as described by Ferguson (1988).
Plants of this O. chlorotica variety may reach 2(2.5) m tall and usually form a single trunk that can reach 20 to 30 cm in diameter. Plants are often upright, but some spreading may occur. Cladodes are suborbicular or orbicular and may be about 12(20) cm across all diameters. Yellow, deflexed spines (2-6), 1-3 cm long, are present in most areoles. Though most populations have very spiny pads, some populations are almost spineless (as near Congress, AZ). The trunk is covered with stout spines up to 5 cm long. Glochids can become prominent and robust on older pads, up to nearly 2 cm long.
O. chlorotica chlorotica has modest, yellow flowers about 2 inches across. A pale red blush may occur on the interior near the base of tepals. The abaxial tepals may have pale reddish veins. Filaments are white to yellow. Anthers, style, and stigma are white, yellowish, or pale green. Fruit is semi-spherical, egg-shaped, or barrel-shaped, 30-60 × 18-40 mm. The fruit pulp of this prickly pear is often colorless and without flavor. Seeds are yellowish, approximately 3.5-4 × 3-3.5 mm, reniform to subcircular, flattened or warped, with a 0.1-0.5 mm girdle.
See the original original description. O. chlorotica is diploid.
An early photograph of this prickly pear (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.
The plant is found in NV, CA, much of AZ, and barely into southwestern UT. It is also found in extreme southwest NM. Typically, O. chlorotica chlorotica grows in well-drained, rocky soils, sometimes between boulders or on cliff faces. However, this Opuntia species may grow in deep soils as near Wickenburg, AZ.