[2] Gymnocalycium bayrianum grows individually with blue-green, reddish, flattened, spherical shoots and reaches heights of 4 to 5 centimeters with diameters of up to 10 centimeters.

The six to ten ribs are broad and flat at their base and notched above each areole.

The usually five bent-back, light brown marginal spines have a darker tip and turn gray with age.

[3] Gymnocalycium bayrianum is widespread in the Argentine provinces of Salta and Tucumán at altitudes of 1000 to 1500 meters.

The specific epithet bayrianum honors Alfred Bayr (1905–1970), a cactus lover and former president of the Society of Austrian Cactus Friends.