Slender, usually simple, 2-5 dm, with 1 or 2(3) terminal and subterminal umbels, normally with 3 lf-bearing nodes, the lower and upper each with a pair of small lvs, the middle with a whorl of 4 much larger ones, or the lvs rarely all opposite in 4 pairs; lvs thin, lanceolate or lance-ovate, the larger 6-12 cm, acuminate, cuneate to a conspicuous petiole; peduncles 1-4 cm; cor pink to white; its lobes 4.5-6 mm; hoods 4-5 mm, much exceeding the gynostegium, the lateral margins bearing a prominent, sharp, inflexed tooth near or below the middle; horn flattened, sword-shaped, falcately incurved; fr erect on erect pedicels, very slender, 8-12 cm. Dry upland woods; Vt. to Va. and in the mts. to n. Ga., w. to s. Ont., Ill., s. Io., and Okla., with a minor disjunction e. of the Mississippi R. May, June.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent in the southern part of the state in dry woodland. The reports from northern Indiana are dubious and if it occurs there it is very rare. There are no reports or specimens from the southwestern part of the state.