About Echinocactus polycephalus subsp. polycephalus
This cactus, currently classified as Echinocactus polycephalus subsp. polycephalus, was previously referred to as Homalocephala polycephala. Its stems sometimes grow alone, but more often form clusters that can contain up to 30 individual stems. Stems reach 30 to 60 centimeters in height and 10 to 20 centimeters in diameter, and feature 13 to 21 distinct ribs. Each areole produces four central spines, which are reddish with a faint purplish tint that fades to gray as the spines age. These central spines are irregularly arranged: the lowest spine curves downward, while the others are generally straight and crisscrossed, growing to 6–7.5 centimeters long. There are also 6 to 8 irregularly distributed radial spines that resemble the central spines in appearance, measuring 3–4.5 centimeters long; all spines of this cactus range in color from yellow to red. The cactus produces yellow flowers, each marked with a central pink stripe, that measure approximately 5 centimeters in both length and diameter. Its fruits are 1.2 to 2 centimeters long and densely covered in woolly white hairs, which gives the species its common name cotton top cactus. Its common clustering growth habit also gives it the alternative common name many-headed barrel cactus. This cactus is known to be difficult to grow in cultivation, and is rarely found in private or public cactus collections. It is distributed across the Mojave Desert region of Arizona, California, and Nevada in the United States, and also grows in the Sonoran Desert region of southern California and northern Sonora, Mexico. It inhabits rocky hills and slopes at elevations between 30 and 750 meters, growing in some of the most extreme arid environments of the American Southwest, including Death Valley National Park and the Mojave National Preserve in Southern California.
