Gymnocalycium baldianum (Speg.) Speg. is very beloved for its very eye-catching flowering even at a very small size. It flowers readily from an early age, and offers no cultivation difficulties. Its stem is flat to globose depressed, up to 13 cm in width, greyish-brown to blue-green (rather variable in colour in cultivation, and in some specimens it is almost blue-black). The 9 to 10 broad ribs are divided by deep grooves into tubercles.
The genus name Gymnocalycium (from Greek, "naked calyx") refers to the flower buds bearing no hair or spines.
Gymnocalycium baldianum
Gymnocalycium baldianum is approximately 5 cm tall and comes in a ⌀ 5.5 cm pot.