Homalocephala polycephala
Homalocephala polycephala, synonym Echinocactus polycephalus, is a cactus that is native to the United States and Mexico.
Description
The stems of Homalocephala polycephala are sometimes solitary, but more often in clusters of as many as 30, grow 30 to 60 centimeters tall and 10 to 20 centimeters in diameter. Its stems are marked by 13 to 21 ribs. The areoles bear four central spines, which are reddish with a slight purplish hue and become gray with age; these spines are irregularly arranged, with the lowest one curving downwards and the others generally straight and crisscrossed. The central spines reach lengths of 6–7.5 cm. The spines are yellow to red. Additionally, 6 to 8 radial spines, also irregularly distributed, are similar in appearance to the central spines and measure 3–4.5 cm long. The cactus produces yellow flowers, each with a central pink stripe, measuring approximately 5 cm in both length and diameter. The fruits are densely woolly covered in white hairs that are 1.2 to 2 cm long, giving the common name cotton top cactus. The tendency of the cactus to cluster causes it to also be called many-headed barrel cactus.They have a reputation for being difficult in cultivation, and are rarely seen in cactus collections.