Mammillaria melanocentra is a short, stocky and glaucous perennial cactus species with large tubercles. Each head is surrounded by a complete ring of star-like dark pink flowers. It originates in Northern Mexico (Coahuila, Durango, Nuevo Leon, and Tamaulipas, Mexico).
Stem: Depressed-spherical, to short-cylindric and rather flattened at the top, up to to 16 cm high and 10-12(-15) cm in diameter, glaucous-green.
Tubercles: in 8 and 13 spirals, firm, large, pyramidal, strongly four-angled, keeled up to about 1.4 x 1.4 cm, their axils with much white wool at first, without bristles. With latex.
Radial spines: (4-)6-9(-13), stout-subulate, (6-)15 to 20(-22) cm long, white, brownish or black, unequal, the lowermost longest.
Central spines: Usually solitary, occasionally up to 3, stout, awl shaped, usually ascending, black when young, later light grey, 2 to 3 cm long, greatly overtopping the stem black, becoming brownish grey later.
Flowers: Whitish to bright pinkish red or carmine with darker midline, approx. 2 x 2 cm long and in diameter, the segments linear, acute.
Blooming season: Flowers are produced in spring over a several weeks period.
Fruits: Pink or red, club-shaped, pink to scarlet, to 30 mm long.
Seeds: Brown.
Exposition: Full sun to light shade.
Watering: Water regularly in summer but do not over-water. Keep dry in winter. Hardy down to -4°C.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz
