Blossfeldia liliputana. USDA 8b-10. Hardy to 15° F. Light shade.  Solitary or clumping miniature cactus, up to 0.5" in diameter.  Requires good drainage, little water summer,  no water in winter. Small pinkish and white flowers. Blossfeldia are the smallest of the cacti. Origin: Southern Bolivia, northwestern Argentina, at elevations of 4000 to 12000 feet.