This branching decumbent cactus has bright green stems up to 20mm (¾in) wide covered in cylindrical tubercles with some wool in the axils. It is densely covered in white to brown needle like spines and the red funnel-shaped flowers appear in summer. 

Hardiness zones 10 to 11 

Mammillaria viperina is naturally found in North America growing in southern Mexico in an open sunny position on stony well drained moderately fertile soils and tolerates drought or high temperatures and is frost tender.

This cactus is grown for its spreading habit and is planted in rockeries or arid gardens as a specimen. It is also used as a container plant for indoor gardens or bright conservatories establishing from division in 1 to 2 years. It is suitable for coastal or inland regions and is planted against a sunny wall. ID 2095

Mammillaria (măm-i-LAH-ree-a) viperina (vy-per-ENA)

Cactaceae (kak-TAY-see-ee)