Ferocactus gracilis H.E. Gates subsp. gracilis Ferocactus gracilis H.E. Gates subsp. gracilis in Cact. Succ. J. (Los Angeles) 4: 323. 1933 sec. Hunt 2016=Ferocactus peninsulae var. gracilis (H.E. Gates) G. Unger, Gross. Kugelkakteen: 193. 1992 syn. sec. Guzmán & al. 2003