[2] Acanthocalycium rhodotrichum usually grows in groups with erect or ascending, cylindrical, dull green shoots that reach heights of 30 to 80 cm (12 to 31 in) with a diameter of up to 12 cm (4.7 in).

The single central spine, which can also be absent, is bent slightly upwards and is up to 2 cm (0.79 in) long.

The spread and slightly curved four to eight radial spines are up to 2 cm (0.79 in) long.

[3] Acanthocalycium rhodotrichum is widespread in the Brazilian state of Mato Grosso do Sul, in Paraguay and in northeast Argentina at altitudes of up to 500 meters.

[4] Recognized subspecies:[2] The first description as Echinopsis rhodotricha by Karl Moritz Schumann was published in 1900.