Opuntia mesacantha var. microsperma (Engelm. & J.M.Bigelow) J.M.Coult. in Contr. U.S. Natl. Herb. 3(7): 429. 1896 Opuntia mesacantha var. microsperma (Engelm. & J.M.Bigelow) J.M.Coult. in Contr. U.S. Natl. Herb. 3(7): 429. 1896Taxon for this nameOpuntia mesacantha var. microsperma (Engelm. & J.M.Bigelow) J.M.Coult.