Epipactis helleborine (L.) Crantz
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Erect from a short, praemorse rhizome, to 8 dm; lvs sessile and clasping, ovate to lanceolate, the lower to 10 cm, the upper progressively smaller; raceme 1–3 dm, many-fld, its bracts linear or narrowly lanceolate, the lower surpassing the fls; sep and lateral pet lance-ovate, 10–14 mm, acute, dull-green, strongly veined with purple; lip greenish and purple; 2n=36–44. Native of Europe, now widespread in our range along roadsides and in woods. July, Aug. (E. latifolia; Serapias h.)