Finely hairy perennial, 3-6 dm, simple; lvs alternate, sessile, lanceolate, 2-5 cm, acute, entire, 3-nerved, the upper progressively smaller; fls solitary in the uppermost axils on short pedicels, forming a leafy spike-like raceme; bractlets 1 cm; cal 2 cm; cor 3-3.5 cm, yellowish on the tube, purplish distally; fr 10-12 mm, the fruiting cal with 12 strongly projecting ribs; 2n=32, 36. Moist sandy soil; s. N. Engl. to Fla. and Tex., and locally in Tenn. and e. Ky.; very rare. June, July. (S. australis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.