Scheer Cory-cactus, Sheer's Strong-spined Cory-cactus, Scheer's Beehive Cactus

Edward F. Anderson’s The Cactus Family recognizes three subspecies of Coryphantha robustispina:

- subsp. robustispina ...Read Moreis typically larger and has a single curved or hooked central spine; it occurs primarily in Pima County, Arizona northern Sonora, Mexico. It has been designated as Threatened (under the name C. scheeri var. robustispina) under the Endangered Species Act and is protected by Arizona state law.

- subsp. scheeri has straight central spines, and occurs in primarily in an area beginning in Eddy and Chavez Counties in New Mexico, extending south through Texas, and into Chihuahua and Coahuila Mexico.

- subsp. uncinata has either curved or straight central spines on mature stems, and may have curved central spines on immature stems. It occurs primarily in an area including Cochise County, Arizona, Dona Ana County, New Mexico, El Paso County, Texas, and northern Chihuahua, Mexico.

Coryphantha robustispina is reputed to be difficult in cultivation, and quite sensitive to overwatering; grafting may be helpful.

Here's a list of more of the current synonyms of this plant. Pending ongoing research, some of these 'might' become a subspecies or varie...Read Morety of this species.
Coryphantha scheeri var. valida, Echinocactus muehlenpfordtii & Mammillaria engelmannii.