Acanthocalycium

Morphological Summary

Genus of cacti endemic to Argentina with four accepted species. The globular to short-cylindrical, very spiny stems produce tubular flowers with scales and spines on the floral tube — a character giving the genus its name ("spiny calyx," from Greek akanthos + kalyx). They inhabit arid and semi-arid zones of the Andean provinces of central-northwestern Argentina, especially on rocky slopes and ravines between 500 and 2,500 m.