Mammillaria wrightii var. wilcoxii (Toumey ex K. Schum.) W.T. Marsh.  
Family: Cactaceae
Wilcox's nipple cactus,  more...
[Mammillaria meridiorosei Castetter, Pierce & Schwerin,  more]
Mammillaria wrightii var. wilcoxii image
Sue Carnahan  
Mammillaria wrightii var. wilcoxii
Mammillaria wrightii var. wilcoxii image
Sue Carnahan  
The National Science Foundation
This project made possible by National Science Foundation Award 1410069