Glabrous perennial 3-9 dm; stems 1-several from the base, erect-ascending, simple below the infl, prominently ridged-striate above; lvs mostly 25-50 below the infl, thin, elliptic to oblanceolate or obovate, the larger ones 1.5-3.5 cm × 4-10 mm, the lower opposite, the upper often alternate; infl ±elongate-paniculiform, with slender, spreading branches; pedicels sharply angular, 1-4 mm; sep lanceolate to ovate, acute, 1.5-3 mm, entire or the inner with a few tiny marginal glands; pet yellow, 3-5 mm; fr depressed-globose, scarcely 2 mm, pale, splitting freely into 10 mericarps, shattering and falling; false septa nearly complete, glabrous, as also the true septa; 2n=36. Damp or wet woods, swamps, and bogs; Mass. to n. Fla., w. to Mich., se. Mo., and e. Tex. June, July. (Cathartolinum s.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.