About Melocactus curvispinus Hort.Berol. ex Pfeiff.
Melocactus curvispinus grows as a solitary cactus, with depressed, spherical to short-cylindrical, green to glaucous shoots that reach 6–30 cm in height and 8–27 cm in diameter. It has 10 to 16 pointed ribs that can become warty, with sunken areoles located in the rib notches. Its spines range in color from off-white to nearly black, and most are curved. This species has 1 to 4 central spines that measure 15–52 mm long, and central spines may be absent entirely. It produces 6 to 11, and sometimes more, radial spines that are 3–42 mm long; the lowest radial spines are the longest. It bears a small cephalium that is 3–4 cm high and 7–11 cm wide, from which reddish-brown bristles emerge. Flowers grow from the cephalium and extend over 10 mm above it, opening in late afternoon. The flowers are pink-violet, 18–43 mm long, and 10–25 mm wide. Fruits of Melocactus curvispinus are club-shaped, colored pink to bright red or magenta, and are slightly lighter in tone at the base. The distribution of Melocactus curvispinus extends from Mexico to southern Peru, northeastern Colombia, Venezuela, and the Caribbean.
