Stem 3-10 dm; lower 2-4 lvs lanceolate, 10-20 cm; upper lvs abruptly reduced, lance-linear; infl 6-18 נ4-6 cm, rather loose; fls reddish-purple; sep broadly oval or obovate, 6-10 mm; lateral pet ca equaling the sep, obovate-spatulate above a narrow base, erose; lip 13-22 mm, deeply tripartite, the terminal lobe deeply notched, each lobe broadly cuneate- flabellate, with conspicuous radiating veins, erose at the margin, the teeth only 0.5-1 mm deep; spur 22-31 mm. Open, swampy or vernally wet places, often in acid soil; N.J. to O. and Mo., s. to S.C., Miss., and Ark. July, Aug. (Blephariglottis p.; Platanthera p.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.