Mammillaria Grahamii (formerly Mammillaria microcarpa) are natively found in washes in the Sonoran and Chihuahuan deserts across California and Texas, and south to Mexico.
 
An excellent pick for intimate cactus and succelent gardens!
 
Flowers in a halo ring of bright pink or magenta, and therafter produces small red fruit.
 
Fun Fact: Was named after Colonel James Duncan Graham (1799-1851) who also has a mountain in Arizona in his name as well!
 
[sourced from ASU online public library]