Much like no. 15 [Veronica americana (Raf.) Schwein]; lvs more elliptic or obovate, 2-6 cm, broadest near or above the middle, usually broadly rounded above, obtuse to rounded at base, crenate; fls 5-7 mm wide; fr turgid, 3-4 mm wide, not notched; style 1.8-2.2 mm; 2n=18, 36. Native of Eurasia, sparingly established on muddy shores and streambanks from Que. to Mich., s. to N.J. and W.Va. Summer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.