Cochemiea

Cochemiea is a genus of cactus.^[2] The group was previously synonymized with Mammillaria, until molecular phylogenetic studies determined that—when broadly circumscribed—Mammillaria is not monophyletic; thus, Cochemiea has been accepted as a distinct genus.^[3]

Species within the genus Cochemiea are characterized by their elongated, cylindrical stems covered in spirally arranged tubercles. These stems are typically green or bluish-green, measuring 3 to 7 cm in diameter and reaching heights of 7 to 50 cm, with some individuals exceptionally growing up to 200 cm. The areoles bear 7 to 25 radial spines, each 1 to 2 cm long and varying in color from white to yellow or reddish-brown. Additionally, they possess 1 to 6 central spines (occasionally up to 11), measuring 1 to 5 cm in length. These central spines can be white with black tips, reddish-brown, or black. Flowers are zygomorphic, arranged in two rows, and emerge from the axils at the stem apex. They measure 3 to 5 cm in length, open during the day, and are typically red or purple, spherical, and indehiscent with a smooth surface and a scar at the tip. The seeds are black and measure 0.5 to 1 mm in diameter.^[4][5]

The native range of Cochemiea extends from the southwestern and south-central United States into Mexico. Specific locations include Arizona, California, the Mexican Pacific Islands, the Gulf of Mexico region, Nevada, New Mexico, Texas, and Utah. These plants thrive in diverse habitats, from full sun to the shade of shrubs, and can be found on rocky cliffs and canyons at altitudes up to 1,800 meters above sea level.

The genus Cochemiea was initially described by American botanist Mary Katharine Brandegee as a subgenus within Mammillaria in 1897. In 1899, British botanist Frederick Arthur Walton elevated it to its current genus status in the publication Cactus Journal 2: 50. The genus name honors the extinct Cochimí indigenous tribe, who historically inhabited Baja California, a region within the natural distribution of these plants.^[6]

A 2021 molecular phylogenetic study of the "mammilloid clade", which included the genera Cochemiea, Coryphantha, Cumarinia, Escobaria, Mammillaria, Neolloydia and Ortegocactus, showed that it consisted of four monophyletic groups, which the authors re-circumscribed into four genera: Cumarinia; Mammillaria, with a reduced number of species; Coryphantha, expanded to include species previously placed in Mammillaria and Escobaria; and Cochemiea, expanded to include a large number of species previously placed in Mammillaria, as well as Neolloydia conoidea.^[3]

In 2021, Breslin, Wojciechowski and Majure placed the following species in the genus, some already placed there and some moved from Mammillaria, Neolloydia, Neomammillaria and Ortegocactus.^[3] As of January 2026, Plants of the World Online accepted in the genus the species moved by Breslin et al.^[2]