Stem segments circular to obovate to rhombic, 20-40 × 17-30 cm, to 1.5 times longer than wide. Spines (0-)1-5(-12) per areole, absent or at most areoles, chalky white, yellow when wetted, aging gray to black, usually with red-brown extreme bases, longest 20-50(-75) mm. 2n = 66 .
'Flora of North America @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=1 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.