This species is fairly widely distributed in central Mexico. It forms attractive clumps of wooly-topped stems with conical tubercles surmounted by spine clusters of 12 to 18 radials, often with a single down-curved central spine, forming an open network over the body. Satiny, pale yellow flowers to 6 cm diameter often have red filaments, which are thigmotropic (sensitive to touch), enclosing around bee pollinators within seconds to assure greater pollen transfer. This thigmotropism and other features are shared by the more southerly C. calipensis from Puebla and Oaxaca, while C. cornifera is distributed in central Mexico, mainly in Hidalgo and Querétaro. HBG 134249, plants grown from self-fertile seed of HBG 56976, E. F. Anderson 4959, collected July 16, 1979 at km 95.5 along Hwy 120 between Jalpan and Cadereyta, 18.8 km north of Vizarrón, Querétaro, Mexico. $7.
Published in the Cactus and Succulent Journal, Vol. 90 (2), Summer 2018