Melocactus are recognizable by the large cephalium that develops on mature plants. They are native from Brazil to Southern Mexico, including the Caribbean.
Parodia, native to the uplands of Argentina, Peru, Bolivia, Brazil, Colombia and Uruguay. Notocactus, with the center of the genus in Brazil and Argentina, but with members throughout the Eastern side of the Andes.
Euphorbia is one of the largest of the succulent plant families. The genus Euphorbia is found throughout the tropics and semi tropics around the world, with some members of the family growing well into temperate regions.