Frequent throughout the state on the low, wet borders of lakes, ponds, and swamps, in low wet woods, and dredged ditches, and sometimes in roadside ditches. It is commonly found on the inner zone of vegetation of swamps and ponds which become dry in summer. This species is the one used in medicine, The whole plant is used and 15 grains of the powdered plant is an average dose. It is used as a nervine and tonic.
Stems solitary from slender rhizomes, 3-7 dm, puberulent in lines with ascending hairs, or sometimes glabrous; petioles 0.5-2.5 cm; lvs thin, pinnately veined, ovate or lance- ovate, with broadly rounded or subcordate base, toothed, 3-8 נ1.5-5 cm; racemes mostly axillary or on axillary branches, 3-10 cm, bracteate but scarcely leafy except sometimes near the base; cal 1.5-2.5 mm; cor blue (pink or white), 5-8 mm, the short galea evidently surpassed by the lower lip; 2n=88. Moist bottomlands; Nf. to B.C., s. to Ga. and Calif. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.