Notocactus warasii

This plant is original from South America, they are It is easy to grow. The flowers that emerge from it are yellow and very showy.

Recommended temperature zone: USDA: 11-12
Frost tolerance: Keep above 32°F (0°C)
Sun exposure: Light shade to full sun
Origin: Brazil, Rio Grande do Sul
Growth habits: Solitary, up to 2" tall (60 cm), 1' in diameter (30 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.
Propagation:Seeds
Blooming habits: Yellow flowers, 2.5" in diameter (6 cm)

Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz