(This plant comes in a 2.5 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).
Flowers: Pale to bright yellow.
Cultivation and propagation: Grow them in rich, porous soil and let them dry out between waterings. These plants need a minimum temperature of 5-10° C (but occasionally temperatures of a few degrees below 0° are not dangerous).
Sun exposure: It enjoys full sun, and it can take on a near black appearance when kept in bright light. In a shaded position the plants grow faster but are not flat shaped and dark colored.
Characteristically, during the dry season plants retract completely under the ground. This plant is short living (10-15 years).
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz