Mammillaria is one of the largest genera in the cactus family (Cactaceae), with currently about 170 to 190 accepted species and around 99 subspecies. Most of the mammillarias are native to Mexico, while some come from the Southwestern United States, the Caribbean, Colombia, Guatemala, Honduras and Venezuela. The common name "pincushion cactus" refers to this genus and the closely related Escobaria.
The first species was described by Carl Linnaeus as Cactus mammillaris in 1753, deriving its name from the Latin mammilla, "nipple", referring to the tubercles that are among the distinctive features of the genus. Numerous species are commonly known as globe cactus, nipple cactus, birthday cake cactus, fishhook cactus or pincushion cactus (though such terms are also commonly used for related taxa, such as Escobaria or Ferocactus).
Description
The distinctive feature of the genus is the possession of an areole split into two clearly separated parts, one occurring at the apex of the tubercle, the other at its base. The apex part is spine-bearing, and the base part is always spineless, but usually bears some bristles or wool. The base part of the areole bears the flowers and fruits, and is a branching point. The apex part of the areole does not carry flowers, but in certain conditions can function as a branching point as well.
The plants are usually small, globose to elongated, the stems from
Detail of cactus with fruit
Fish hook cactus (Mammillaria beneckei var. balsasoides)
Taxonomy
The genus Mammillaria in the family Cactaceae was proposed by Adrian Hardy Haworth in 1812. Initial spellings varied by authors but Mammillaria is now recognized as the accepted spelling. The first species in the genus was described by Carl Linnaeus in 1753 as Cactus mammillaris. The name Cactus became so confused that the 1905 Vienna botanical congress rejected Cactus as a genus name, and conserved Mammillaria.
