Stout, usually simple, to 1 m; lvs several pairs, almost always opposite, broadly oblong to ovate, 8-12 cm, abruptly acuminate to obtuse and apiculate, cuneate to a petiole; umbels 1-4, compact, usually many-fld; cor white or pink-tinged, its lobes 7-9 mm; column very thick, expanded above; hoods divergent, strongly ventricose or subglobose, the body saccate, the lateral margins infolded around the horn, with or without an obscure lateral lobe near the middle; horns strongly flattened, obliquely obovate, abruptly contracted to a short inflexed beak; fr erect on deflexed pedicels. Upland woods and thickets; Conn. and s. N.Y. to n. Fla., w. to O., s. Ill., se. Mo., and Tex. June. (Biventraria v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.