Rank, glabrous annual to 4 m; lfls 30-70, narrowly oblong, 1-3 cm; fls 2-6 in short racemes, yellow mottled with purple, 1.5-2 cm; fr 10-20 cm נ3-4 mm, subtended by the persistent cal and tipped with the long, slender style; 2n=12. Alluvial soil; tropical Amer. to Fla., Tex., and s. Mo., and rarely adventive along the coast in our range. (S. macrocarpa)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.