Mammillaria geminispina. USDA: 10. Light shade. Little water. Hardy to 28°F. Cylindrical 2-3' wide mound, each stem up to 4" diameter. Origin: Central Mexico.

Mammillaria microcarpa (Mammillaria grahamii)Sunset: 8-24; USDA: 8-10. Light shade. Heat tolerant. Little water. Hardy to 10°F. Cylindrical barrel grows to 6" tall; Solitary or forming mounds. Origin: California to Texas, northwestern Mexico.

Mammillaria parkinsonii (Owl's eyes). USDA: 9b-11. Light shade. Little water. Hardy to 25°F. Cylindrical barrel grows to 10' tall; 20" wide, forming mounds. Origin: Mexico.

Mammillaria pettersonii (Golden ball) related to Mammillaria apozolensis. USDA: 9. Protect from afternoon sun. Hardy to 28°F. Low to moderate water. Needs good drainage. Deep pink flowers in rings appear in spring to summer. Globular growth to 8" +. Origin: Guanajuato, Mexico