Turbinicarpus knuthianus

This is a still small seedling, grown under part shade and showing weak spines. It is eager to produce buds for about a year now, but needed to grow a bit to be finally able to fully develop them.
Turbinicarpus (Gymnocactus) knuthianusis is an old classic, still not common in collections. It is easily grown from seed, or sometimes available from the specialized nurseries.