Structure and identification
The stem is spherical or ovoid, solitary or offsetting, with a glaucous green epidermis. The thickened root narrows upwards into a neck. Tubercles are loosely arranged, obliquely tipped, with a flatter upper side and keeled underside. Red glands lie in grooves and axils. Several central spines spread forwards and sideways. The authors describe large pale yellow flowers with a sweet scent. [Dicht and Lüthy 2005, p. 52–53]
Habitat and variation
The monograph indicates sites in Tamaulipas, in the Jaumave region, on sandy-gravelly alluvium near rivers, beneath shrubs. Comparing it with C. wohlschlageri, the authors emphasise tubercle arrangement and fewer central spines. Both species have a thickened root with a narrower part connecting it to the stem. [Dicht and Lüthy 2005, p. 52–53]