This is a widespread northern perennial of base-rich swamps and streambanks. The only records are from BOON (B), JEFF (BT), OLDH (B), and ROBE or NICH (PH, MICH, WIS etc., C.W. Short, "Blue-licks"; see also, Pennell 1935). None are dated after 1950. The closely related Eurasian species, beccabunga, is also expected; it has leaves broadest near or above the middle (versus towards base) and shorter styles (1.8-2.2 mm versus 2.5-3.5 mm). Both taxa differ from anagallis-aquatica (and its segregates) in their distinctly petiolate leaves (versus at least midle to upper leaves sessile); see W and his citations.