Your support is critical to our success.
Bull. Acad. Roy. Sci. Bruxelles 5: 492 (t. 1). 1838
Work can be freely used for any purpose, even commercial one. Original author of image doesn't have to be mentioned under shared or derived work.
More about licenses and author rights.
Ariocarpus retusus LH453 Las Tablas, SLP. (left) and Ariocarpus retusus SB240 Matehuala (Right) This species is quite variable