Erect, 8-20 dm, usually with a few erect branches; lvs in whorls of 3-6, on petioles 3-10 mm, lanceolate to narrowly oblong or oblanceolate, acuminate, finely and sharply serrate, glabrous to villous beneath; spikes erect, 5-15 cm, with numerous, crowded, divergent fls; cor 7-9 mm; fr narrowly ovoid, 4-5 mm; 2n=34. Moist or dry upland woods and prairies; Vt. to Ont. and Man., s. to Ga. and La. June-Aug. (Veronica v.; Leptandra v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Somewhat frequent in the lake and prairie areas of the state and infrequent to rare or absent elsewhere. It is found in small colonies or as scattered plants and possibly originally occurred in small prairie openings in every county of the state. Its moisture requirements vary from those of a marsh to a dry, wooded slope. The plant is peculiar in that one can rarely predict where it may be found and that it has no special plant associate. On the whole, it seems to prefer sandy soil and prairie habitats. The plants of this species vary greatly and some of the extremes have been named, but Penell regards the species as polymorphic. The leaves vary from 3-6 in a whorl; the pubescence of the stem and lower surface of the leaves from glabrous to velutinous; and the flowers from white to purplish. The plant has long been used in medicine [the root is a powerful emetic and cathartic] and is known to the eclectic physician as Leptandra, one of its generic synonyms.