Gymnocalycium monvillei

Gymnocalycium monvillei grows individually, rarely sprouting, with dark green, spherical to flattened spherical shoots, which reach heights of 6 to 8 centimeters with diameters of up to 20 centimeters and forms a massive taproot. As plants age, they sometimes become shorter and more columnar. The 10 to 17 mm wide, blunt ribs are clearly divided into humps with conspicuous chin-like projections. The areoles are oval and, in addition to the spines, have a dirty-whitish wool felt. The strong, thick, slightly curved thorns are yellowish and have a reddish or purple base. There are one to four central spines up to 6 centimeters long, which can sometimes be missing. The 7 to 13 marginal spines are 3 to 4 centimeters long.

The white, red-tinged, partially monoecious flowers reach a length of 3 to 8 centimeters and a diameter of 4 to 9 centimeters. The stamens are whitish with yellowish pollen, the style is whitish yellow. The spherical fruits are green to cloudy orange-red and reach a diameter of up to 2 centimeters.^[3]

• 
  Gymnocalycium monvillei subsp. horridispinum
• 
  Flowering G. monvillei

• Gymnocalycium monvillei subsp. achirasense (H.Till & Schatzl) H.Till
• Gymnocalycium monvillei subsp. horridispinum (G.Frank ex H.Till) H.Till
• Gymnocalycium monvillei subsp. monvillei

Gymnocalycium monvillei is distributed in central and northern Argentina, in the provinces of Córdoba and San Luis at altitudes of 500 to 2700 m.^{[citation needed]}