From Hidalgo and San Luis Potosi, Mexico, Stenocactus coptonogonus differs somewhat from other Stenocacti in that the ribs are thick and not wavy. It could almost be mistaken for a Ferocactus with it's thick sharp spines. Stenocactus coptonogonus gets to be about 4 inches across and produces a pale lavender flower with darker purple midstripes.
     I got this one at Tohono Chule Park and it seems to be doing fine. I'll post a flower pic when I finally get one.