Wikipedia
Discocactus
Discocactus is a genus of tropical cactus. The name comes from the ancient Greek (=disc) because of its shape. Discocactus plants are endemic to southern Brazil, eastern Bolivia, and northern Paraguay. These species are in the risk of extinction in the wild.
The plants have a slightly flattened spherical shape. The areoles bear sharp spines. At the apex of the adult plants, there is a wooly cephalium, white or shaded with yellow or grey. The white nocturnal flowers appear on the sides of the cephalium. The fruits are pink or red and contain black seeds.
Image:Discocactus horstii.jpg| Discocactus horstii Image:Discocactus araneispinus habit.jpg| Discocactus zehntneri Image:Discocactus placentiformis.jpg| Discocactus placentiformis