The support structure of Cholla cacti provides stabilization via hollow cylindrical struts joined as trusses.


"Some cacti (such as the cholla), though, have supportive columns of branched and rejoining struts--trusses in the form of hollow cylinders with perforated walls." (Vogel 2003:437-438)

Comparative Biomechanics: Life's Physical World, Second EditionPrinceton University PressFebruary 28, 2017
Steven Vogel