Discocactus araneispinus Cultivation and propagation: Discocactus araneispinus are the easiest species of the genus to grow, but even so it isn't a plant for beginners, in fact collectors consider the Discocactus to be rarities with requires skilful cultivation. It is rather difficult to grow and frost tender, it can’t stand cold, or even fairly cool temperatures and should be kept at above 15° C if grown on its own roots (8°C if grafted). Need full sun or afternoon shade. They are slow growing and very rot prone when kept on their own roots and though they can’t endure long stretches of total dryness, too much water will rot them, as their weak root systems tend to be inefficient at sucking up water from wet soil. They generally resent being repotted and can take a long time to establish. When grown to maturity, however, it possesses an exotic look shared by no other cacti, and it generally attract a lot of attention. Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz
