7. Thalictrum dioicum Linnaeus, Sp. Pl. 1: 545. 1753.
Early meadow-rue, quicksilver-weed, pigamon dioïque
Roots yellow to light brown, fibrous, from stout caudex. Stems erect, 30-80 cm, glabrous or glandular. Leaves basal and cauline, petiolate. Leaf blade 1-4×-ternately compound; leaflets reniform or cordate to obovate or orbiculate, apically 3-12-lobed, 10-45 mm wide, lobe margins often crenate, surfaces abaxially glabrous or glandular. Inflorescences terminal and axillary, panicles to corymbs, many flowered. Flowers: sepals greenish to purple, ovate or obovate to oval, 1.8-4 mm; filaments yellow to greenish yellow, 3.5-5.5 mm; anthers 2-4 mm, mucronate to acuminate; stigma purple. Achenes (3-)7--13, not reflexed, sessile or nearly so; stipe terete, 0-0.2 mm; body ovoid to ellipsoid, not laterally compressed, 3.5-5 mm, glabrous, very strongly veined, veins not anastomosing-reticulate; beak 1.5-3 mm.
Flowering spring (Apr-Jun). Rocky woods, ravines, and alluvial terraces, mountains and piedmont; 10-1000 m; Man., Ont., Que.; Ala., Conn., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Pa., R.I., S.C., S.Dak., Tenn., Vt., Va., W.Va., Wis.
Glandular plants of Thalictrum dioicum have often been misidentified as T . revolutum despite important differences, especially the leaflets having crenate versus entire lobe margins, respectively. The stamens in both T . dioicum and T . revolutum are pendulous.
Native Americans used roots of Thalictrum dioicum in various preparations to treat diarrhea and vomiting and for heart palpitations (D. E. Moerman 1986).