Mammillaria gigantea is a species of cactus in the subfamily Cactoideae native to Mexico. It is named for its large size.
Mammillaria gigantea is a cactus that grows low and almost cake-shaped, often slightly sunken at the top, and covered in white wool felt. Its blue-green body is 9 to 10 cm high and 15 to 17 cm in diameter, with densely packed warts that produce milky juice. The axillae are covered with white wool. It has up to 12 small, fine-needle, straight white radial spines, each up to 3 mm long, and 4 to 6 strong, usually curved central spines, with the lowest one reaching up to 2 cm. New central spines are yellow-brown with dark tips, later becoming yellowish, white to horn-colored, and reddish at the base.
As with all Mammillaria, the flowers appear in a wreath. They are green-yellow and about 15 mm in diameter. The fruits are pink to greenish, and the seeds are brown.[1]
Mammillaria gigantea is found in the mountainous regions of the Mexican states of Guanajuato, Durango, San Luis Potosí, and Querétaro, at altitudes between 1750 and 2400 meters.[2]
It was first described in 1898 by Karl Moritz Schumann.[3] The specific epithet "gigantea" comes from Latin and means "enormously large," referring to the plant's size.[4]