Obovate-cylindrical, 6 by 8 cm., somewhat cespitose: tubercles
ovate, terete, 10 mm. long, grooved to the base, with naked
axils: radial spines 10 or 11, straight and spreading, rigid,
blackish (becoming ashy with age), black-tipped, 12 mm. long;
central spine large, more or less spotted, erect, 25 to 35 mm.
long: flower 13 mm. long, pinkish: fruit unknown. Type in Herb.
Coulter.
San Luis Potosi.
Specimens examined: San Luis Potosi (Eschanzier of 1891).
Somewhat resembles C. tuberculosus in general appearance, but
very different in spine characters.