Acanthus ring size - 10In architecture, an ornament may be carved into stone or wood to resemble leaves from the Mediterranean species of the Acanthus genus of plants, which have deeply cut leaves with some similarity to those of the thistle and poppy. Both Acanthus mollis and the still more deeply cut Acanthus spinosus have been claimed as the main model, and particular examples of the motif may be closer in form to one or the other species; the leaves of both are in any case, rather variable in form. The motif is found in decoration in nearly every medium.

The relationship between acanthus ornament and the acanthus plant has been the subject of a long-standing controversy. Alois Riegl argued in his Stilfragen that acanthus ornament originated as a sculptural version of the palmette, and only later, began to resemble Acanthus spinosus