The Bromeliads, like Cacti and Agavaceae are a New World family.
From Mexico and Southern US. Usually having heavy spination and relatively small flowers, the fruits are copiously woolly. Includes the "Golden Barrel Cactus".
There are around 200 species in the genus, most from Mexico, some from the southern United States and into South America.
Both genera are from South Africa and are closely related.
Melocactus are recognizable by the large cephalium that develops on mature plants. They are native from Brazil to Southern Mexico, including the Caribbean.