Triphora trianthophora (Sw.) Rydb.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Stem 1–3 dm, nodding, straightening as it grows; lvs sessile, ovate, 1–2 cm; fls ephemeral; sep and lateral pet lanceolate, 1.5–2 cm; lip 1.5–2 cm, with 3 prominent green ridges, crisped at the tip, the lateral lobes upturned. Rich moist woods, often on rotten logs; s. Me. to s. Wis., s. to Fla., Tex., and C. Amer. Aug., Sept. (Pogonia t.)