Stenocactus coptonogonus (Lemaire) A. Berger ex A. W. Hill
Growth Habits: Solitary slow-growing cactus,2 to 4 inches tall (5-10 cm), 3 to 4.5 inches wide (7-11 cm)
Scientific name: Stenocactus coptonogonus
Common names: None known.
Synonym: Ferocactus coptonogonus, Echinocactus coptonogonus, Echinofossulocactus coptonogonus
Etymology: Stenocactus, From the Greek words stenos, meaning narrow, and kaktos, meaning thistle.
coptonogonus, unknown.
Origin: Mexico (Hidalgo, San Luis Potosi)
Light: Full sun to light shade.
Compost: Standard cactus mix is ok.
Water: Regular from spring to autumn allow soil to dry between waterings. Dry in winter.
Flower: Purple and White.
Min temp: Down to about -10C (14F) for short periods.
References.
http://www.cactus-art.biz
http://www.desert-tropicals.com
http://www.cactiguide.com
Comments. Quite an easy plant to grow, good for beginners, takes up little space in a collection.
Image showing flower buds.