Because of the small size of its flowers, Water Speedwell is relatively inconspicuous. This is one of the wetland Veronica spp., rather than one of the weedy Veronica spp. that are found in lawns and along roadsides. Because of the variations of local populations across its wide distribution, Water Speedwell has an unstable taxonomic history. Some authorities refer to this species as Veronica catenata, Veronica comosa, and other scientific names. Because it is not uncommon to find specimens with mixed characteristics and there is a lack of consensus among authorities, these postulated species have been lumped together as variations of Veronica anagallis-aquatica. Water Speedwell differs from other wetland Veronica spp. by the large number of flowers/capsules per raceme (20-65) and its sessile or clasping leaves. It is much larger in size than the weedy Veronica spp. that are found on lawns and roadsides; species in this latter group usually produce individual flowers from the axils of the leaves, rather than racemes of numerous flowers.