Mammillaria spinosissima Un Pico
(This plant comes in a 3.5 inch pot. You will receive a very similar plant to the one in the picture. It may or may not be blooming at the time of your purchase. The plant is shipped in its pot to prevent any damage to the roots).
Cultivation and propagation: It is an easy to grow cultivar It is a great starter plant for the cactus grower, that readily builds up into a cluster of stems highlighted by reddish spines, further decorated by rings of purple-pink blooms.
Watering: Water regularly in summer, but do not overwater. Keep dry with ample airflow in winter.
Hardiness: It is quite frost resistant if kept dry.
Exposition: Outside bright sun, filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Subject to sunburn if exposed to direct sun for too long. Tends to bronze in strong light, which encourages flowering and heavy wool and spine production.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz