Mammillaria uncinata

Mammillaria uncinata typically grows alone, but can also form clusters. Its flattened, spherical to globular shoots are dark blue-green in color, measuring 6 to 10 cm (2.4 to 3.9 in) in height and 8 to 10 cm (3.1 to 3.9 in) in diameter. The plant features firm, pyramidal tubercles that are angular at the base and exude a milky sap. The axils of the tubercles are initially covered with wool, which later becomes bare.

The cactus has a central spine that is pinkish-gray to dark purple-brown, with a dark tip, and can be up to 1 cm (0.39 in) long. It also has 3 to 6 radial spines that are straight or slightly curved; the uppermost ones are shorter and stronger. These radial spines are pinkish to grayish-white and measure about 5 to 6 mm (0.20 to 0.24 in) in length.

The flowers are yellowish or white with a reddish-brown central stripe. They are 1.5 to 2 cm (0.59 to 0.79 in) long and up to 1.5 cm (0.59 in) in diameter. The fruits are club-shaped, purple-red, and grow up to 1.8 cm (0.71 in) long. They contain brown seeds.^[2]

Mammillaria uncinata is a cactus species native to several Mexican states, including Hidalgo, San Luis Potosí, Mexico, Morelos, Puebla, Oaxaca, Guerrero, Durango, Querétaro, Aguascalientes, Michoacán, and Jalisco at elevations between 1,500–2,800 m (4,900–9,200 ft).^[3]

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  Plant in habitat near Cerritos, San Luis Potosí
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  Habitat in Dolores, Hidalgo
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  Habitat in Dolores, Hidalgo