Melocactus matanzanus aka Dwarf Turk's Cap Cactus

Melocactus matanzanus is a small cactus native to Cuba. It belongs to the cactus family, Cactaceae. Gardeners know it as the dwarf Turk's cap cactus. It grows in coastal scrub on serpentine rock outcrops. Low, drought-adapted plants share this habitat. Its home has a seasonally dry tropical climate. LLIFLE lists it as Critically Endangered. Forestry work threatens its habitat.

This perennial succulent grows as a single, rounded stem. The pale green body may look slightly flattened. It reaches about 0.26–0.30 feet [0.08–0.09 metres] tall and wide. Eight or nine sharp ribs divide the stem. Some plants have as many as thirteen ribs. Small spine-bearing pads, called areoles, line these ribs. Each bears several curved outer spines and one central spine. The spines range from white through cream to brown. They turn grey or whitish with age.

An older plant forms a cap called a cephalium. This is the part that bears the flowers. Wool and dense orange-red bristles cover its surface. The cap adds height above the round green body. Plants may first flower at four to five years old. Small pink to deep red flowers appear in midsummer. They form a ring within the cap. Each opens near noon and lasts only a few hours. Pink to lilac-pink berries follow, with a club-like shape. Ripe fruit remains on the cap. The evidence does not establish edibility or toxicity.

This cactus suits a collection, but needs careful care. It can grow quite fast when conditions suit it. Use a porous cactus mix and a well-drained pot. Its weak roots dislike disturbance and recover slowly after repotting. Let the soil dry well between waterings. Do not leave it dry for long periods. Too much water can rot the roots. It needs some winter water, unlike many other cacti. Do not feed it during winter.

Warmth throughout the year helps this tropical species survive. Keep it above 8–12°C rather than testing its cold tolerance. LLIFLE reports brief survival near 4°C, but cold can cause severe harm. Seed is the stated means of propagation. Sow into a light, sandy mix in late winter or early spring. Germination works best at 18–22°C. Keep the seed tray covered so seeds do not dry out.