Cylindropuntia alcahes subsp. mcgillii (Rebman) U. Guzmán Cylindropuntia alcahes subsp. mcgillii (Rebman) U. Guzmán, Cat. Cact. Mex.: 48. 2003 sec. Guzmán & al. 2003=Cylindropuntia alcahes var. mcgillii Rebman in Madroño 62: 50. 2015 syn. sec. Guzmán 2009