From the elliptical areoles arise submissive, gray thorns that have a darker tip.

Your pericarpel and the flower tube are covered with dark pointed scales and brown to white hair and bristles.

The spherical, hard-fleshed fruits tear open and reach a diameter of up to 1 cm (0.39 in).

[2] Recognized subspecies:[3] Acanthocalycium thionanthum is widespread in the Argentine provinces of Salta, Tucumán and Catamarca at altitudes of 1500 to 3000 meters.

[5] The specific epithet thionanthum is derived from the Greek words theion for 'sulfur' and anthos for 'flower' and refers to the flower color of the species.