Mammillaria gracilis - THIMBLE CACTUS

Mammillaria gracilis is a small, clustering cactus native to Mexico. It is a popular ornamental houseplant known for its cylindrical, bright green stems that are densely covered in soft, white spines. 
 
Common Names: Thimble Cactus, Mammillaria gracilis, Thimble Mammillaria, Mammillaria vetula ssp. gracilis
Name Meaning: Mammillaria: Latin mammilla, "nipple" or "breast"; gracilis: Latin "slender," "graceful," or "thin".
Plant Family: Cactaceae (cactus)
Native Range: Deserts and dry shrublands of central Mexico
Grow Zone (Hardiness): 9 - 11 NOT FROST HARDY (25°F) Find my zone
Bloom: In late winter to spring, plant produces small, funnel-shaped blooms that are creamy yellow to pale pink, giving way to small, fleshy seed pods that mature from pinkish-white to red. 
Light: Bright, direct light (such as a south-facing window)
Soil: Well-draining
Water: Low
Growth Rate/Habit: Slow-medium/Clumping, clustering
Mature Size:  3 - 6 in. tall x 4 - 5 in. wide
 
SOLD AS A POTTED SPECIMEN, 1 TO 3 INCHES TALL.
 
Photo by Michael Wolf/Wikimedia Commons, CC BY-SA 3.0