Rather small ball-shaped cacti of Mexico and southern states of USA. Quite a diverse group of plants with short of long spines some of which are hooked, and unusual flowers of yellow or red but also green or even black colour. Real beauties, they are, although some consider them to be more difficult to grow than most cacti. Nevertheless a really porous purely mineral potting mix, generous watering but only a few times during the growing season and a lot of sun and heat would certainly make them – and their owner – happy. Now moved to the genus Sclerocactus (I do not care as it changes every month, so while the big boys play with names I use names everybody understands).