Rhizomes tuberous-thickened at the end; stems weak and soft, 1-3 dm; lvs thin, ovate or deltoid-ovate, 2-6 cm, usually more than half as wide, acute, sharply and coarsely undulate-dentate, broadly truncate to more commonly cordate at base; petioles thin and ±flat above, and with a conspicuous thin median wing beneath; racemes rarely with more than 15 fls, elongating to 1 dm in fr, the fls at anthesis all clustered at the still unelongated top; pedicels 2-6 mm, glabrous, spreading or slightly deflexed in fr; sep 1-2 mm, white or pinkish, glabrous; pet 1-2.5 mm, bilobed to about the middle or less; anthers 0.2-0.3 mm; disk nearly obsolete; stigma capitate or inconspicuously bilobed; fr 2-3 mm, unilocular and 1-seeded, not ribbed or furrowed; 2n=22. Moist or wet woods and mossy bogs; circumboreal, s. to N.Y., Ind., Io., and S.D., and in the mts. to N.C., Tenn., and N.M. June-Aug. Ours is var. alpina.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.