Gymnocalycium horstii Buining is a distinctive large cactus. It is smooth, globoid, shiny green up to 20(-25) cm in diameter. It is minimally spined with a green ball-shaped body. Usually solitary or slowly clustering as they age.
The genus name Gymnocalycium (from Greek, "naked calyx") refers to the flower buds bearing no hair or spines.
Gymnocalycium horstii
Gymnocalycium horstii is approximately 25 cm tall and comes in a ⌀ 10 cm pot.