The genus name Gymnocalycium (from Greek, "naked calyx") refers to the flower buds bearing no hair or spines.

[1] The species of the genus Gymnocalycium are low-growing, usually solitary or sometimes small cushion-forming plants with globose, depressed-globular to short-cylindrical stems.

The 4 to 15 (rarely more) ribs are usually broadly rounded, often sinuous, occasionally warty, and often have a "chin" just below the areoles.

The flower cup and the corolla are covered with a few large, broad and obtuse scales that have membranous edges.

[2] Species of the genus Gymnocalycium according to Plants of the World Online as of August 2023[update]:[3] Their main area of distribution is Argentina, part of Uruguay, Paraguay, Bolivia and part of Brazil.