Mammillaria
The genus Mammillaria is one of the largest in the cactus family with currently 200 known species and varieties recognized. Most of the Mammillarias are native to Mexico, but some come from the southwest USA, the Caribbean, Colombia, Venezuela, Guatemala and Honduras. Most Mammillarias are considered easy to cultivate and great for beginners, though some species are among the hardest cacti to grow. This coupled with a prolonged flower period make this a very attractive genus.