Mammillaria hahniana
Mammillaria hahniana, the old lady cactus, is a species of flowering plant in the family Cactaceae, native to central Mexico. It grows to tall by broad. The solitary spherical stems, 12 cm in diameter, are covered in white down and white spines. Reddish purple flowers are borne in spring and summer, sometimes forming a complete ring around the apex of the plant.
Its status is listed as "Near Threatened" by the IUCN Red List.