Mammillaria uncinata

Mammillaria uncinata is a small cactus native to Mexico. It belongs to the cactus family, Cactaceae. Kew describes its life form as a succulent subshrub. It grows in deserts and dry shrubland across Mexico. Its range includes Hidalgo, Oaxaca, Durango, Jalisco, and several other states. Wild plants grow at 4,920–9,190 feet [1,500–2,800 metres] above sea level.

Plants may grow alone or form offsets around the base. LLIFLE describes offset growth as slow, yet also reports ready clump formation in cultivation. The dark blue-green stems stay small. They reach 0.20–0.33 feet [0.06–0.10 metres] tall. Each stem spans about 0.26–0.33 feet [0.08–0.10 metres]. Wild stems lie quite flat, while cultivated plants develop rounder stems. These measurements describe individual stems, rather than the full width of older clumps.

Each spine group has three to six radial spines. These may be straight or have a slight curve. Their colour ranges from pinkish white to greyish white. The upper radial spines are shorter and more stout. A single hooked central spine has a dark tip. Its colour ranges from pinkish grey to deep purplish brown. The central spine can reach 0.033 feet [0.010 metres] long.

Flowers open in spring and summer, and plants flower readily in cultivation. Their funnel-shaped blooms range from pale yellow to creamy white. Brown lines run along the middle of the flower segments. Flowers reach 0.049–0.066 feet [0.015–0.020 metres] long. Their width reaches about 0.049 feet [0.015 metres]. Summer fruits are red to purplish red. They have a narrow cylinder or club shape. Fruits measure 0.049–0.059 feet [0.015–0.018 metres] long.

This cactus grows fast when its growing conditions suit it. Outdoors, it accepts full sun or shade during the afternoon. Indoors, give it strong light with some direct sun. Use a very porous potting mix and a pot that drains well. Water through summer, but avoid excess water, which can cause rot. Keep the plant dry through winter. LLIFLE recommends a potassium-rich feed during summer growth. Dry plants can withstand about 23°F [-5°C]. Some reports claim tolerance down to 10°F [-12°C]. These cold limits depend on keeping the plant dry. Sow seed after the final frost.