Mammillaria nivosa aka Cactus

Mammillaria nivosa is a perennial cactus in the Cactaceae family. Gardeners also call it woolly nipple cactus. Its native range spans parts of the Caribbean. These include the southern Bahamas, Turks and Caicos, and Mona Island. It also reaches the Leeward Islands. It grows on limestone rocks in a seasonally dry tropical climate. Wild plants supply fruit for local food use. The species has a Least Concern conservation rating. Yet building and tourism threaten parts of its habitat.

Plants may grow alone or form mats of many stems. They produce offsets freely and can form clumps within several years. Well-grown older groups reach about 1.3 feet [0.4 metres] across, sometimes more. Each stem measures about 0.26–0.33 feet [0.08–0.10 metres] across. The stems are round or shaped like short columns. Their colour ranges from deep green to bronze. They contain latex. Blunt, cone-shaped tubercles cover the stems, with thick wool in their axils.

Each spine cluster has six to thirteen radial spines. These straight, sharp spines range from yellow to dark brown. They reach about 0.07 feet [0.02 metres] long. A single central spine is usual and resembles the others. Pale yellow flowers open by day in early spring. Each bloom spans about 0.07 feet [0.02 metres] and has yellow stigmas. Dark red, club-shaped fruit follows the flowers. The seeds are brown. The fruit can be eaten raw. The cited food source reports no known hazards. This does not remove the risk from sharp spines.

This tropical cactus needs heat during its growing season. It cannot withstand frost and grows best with warmth year-round. Use a porous growing mix that includes some organic matter. The pot must let excess water drain away. Water on a regular schedule in summer, but avoid excess. Keep the plant dry through winter. It accepts more root moisture than many related cacti. Even so, too much water can cause rot. A potassium-rich feed in summer supports cultivation.

LLIFLE describes this species as easy to grow and quick-growing. It also flowers readily when conditions suit it. Its clumps, spines, flowers, and red fruit provide visual interest. Growers can raise it from seed or divide its offsets. Let detached offsets dry for about two weeks before planting. Spring seed germination takes around one to two weeks under warm conditions. The supplied sources report no known medicinal or other uses.