Much like no. 17 [Veronica anagallis-aquatica L.], often finely stipitate-glandular upwards; lvs entire or subentire, (2.5-)3-5(-8) times as long as wide; racemes often with fewer fls; fls white to pink or pale bluish, 3-5 mm wide; sep less variable, mostly broader and blunter; fruiting pedicels divaricately spreading; fr mostly a little wider than high, sometimes more evidently notched; petiolate-lvd autumnal shoots not formed; 2n=36. Slow-flowing streams and ditches; widespread in the U.S. and s. Can., and in Eurasia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.