Parodia erubescense or Notocactus schlosseri
(This plant comes in a 3.5" 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).
This is red spiny and easy plant to cultivate. It can support quite a lot of water during the growing season. Solitary to shortly cylindrical, upright spherical cactus. It can grow up to 20 cm high and 12 cm in diameter.
The spines are dense, short, stiff and erect; they are russet to orangish colored. Thinner against the body of the cactus the spines become radial and white.
Recommended temperature zone: USDA 9b-11
Frost tolerance: Hardy at least to 20°F (-6°C)
Sun exposure: Sun to partial shade
Growth habits: Solitary spherical cactus, 5" in diameter (12 cm), up to 7" tall (17 cm)
Watering needs: Regular water in summer. Keep rather dry in winter, rots easily if the substrate is wet and cold, tends to lose its roots in winter.
Flowers: Lemon-yellow, up to 5 cm in diameter, with red stigma.
Blooming season: It will usually flower within 3 to 5 years in spring.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz