Mammillaria plumosa

Mammillaria plumosa (feather cactus) is a species of flowering plant in the family Cactaceae, native to Northeastern Mexico.
It grows to 12 cm (5 in) tall by 40 cm (16 in) broad. The clustering spherical stems, 7 cm (3 in) in diameter, are completely covered in white downy spines. White or greenish yellow flowers are borne in late summer.