Epipactis gigantea Douglas ex Hook., Fl. Bor.-Amer. 2: 202, pl. 202. 1839 sec. Soto-Arenas & al. 2007
- =Epipactis americana Lindl. in Ann. Nat. Hist. 4: 383. 1840 syn. sec. Solano Gómez & al. 2020
- =Limodorum giganteum Kuntze, Revis. Gen. Pl. 2: 671. 1891 syn. sec. Solano Gómez & al. 2020
- =Peramium giganteum (Douglas ex Hook.) J.M. Coult. in Contr. U.S. Natl. Herb. 2: 424. 1894 syn. sec. Solano Gómez & al. 2020
- =Serapias gigantea (Douglas) A.A. Eaton in Proc. Biol. Soc. Washington 21: 67. 1908 syn. sec. Solano Gómez & al. 2020
- =Helleborine gigantea (Douglas ex Hook.) Druce in Bull. Torrey Bot. Club 36: 547. 1909 syn. sec. Brown 2003
- =Amesia gigantea (Douglas) A. Nelson & J.F. Macbr. in Bot. Gaz. 56(6): 472. 1913 syn. sec. Brown 2003
- =Epipactis pringlei Gand. in Bull. Soc. Bot. France 66: 293. 1920 syn. sec. Solano Gómez & al. 2020