Publication: Fl. Bor.-Amer. 2: 202, plate 202. 1839.
selected vouchers: WTU
Notes: FNA26: "Two very distinct color forms of this species have been published: Epipactis gigantea forma rubrifolia P. M. Brown, with deep red stems and leaves, and E. gigantea forma citrina P. M. Brown, with lemon-yellow flowers. Both are known from California.
The occurrence of this wide-ranging species in India and Tibet is based on Epipactis royaleana Lindley ex Royle being given as a synonym in a study of the Monocotyledoneae of Karakorum (W. B. Dickoré 1995) and an embryologic study (S. P. Vij et al. 1999)."