This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Similar to the preceding species, perennial by stolons or leafy shoots, glabrous throughout; stem decumbent, usually branched, rooting at the lower nodes, 6'-3° long. Leaves oblong, ovate or oblong-lanceolate, all distinctly petioled, sharply serrate, truncate, rounded, or subcor-date at the base, obtuse or acutish at the apex, 1'-3' long, 1/4' - 1' wide; racemes peduncled, borne in most of the axils, loose, elongated, sometimes 6' long; bractlets shorter than the pedicels; flower blue or nearly white, usually striped with purple, 2" broad; capsule nearly orbicular, compressed, but not very flat, emarginate, 1 1/2" high; seeds flat.
Veronica Beccabunga L., a European brooklime, similar to V. americana in habit, but with crenate or low-serrate broad tipped leaves, is naturalized about Quebec and has been found on ballast about seaports in New York and New Jersey.
Veronica scutellata L. Sp. Pl. 12. 1753.
Glabrous, or very sparingly pubescent, rarely quite hairy, perennial by leafy shoots or stolons; stems slender, decumbent or ascending, leafy, simple or branched, commonly rooting at the lower nodes, 6-2° high. Leaves linear or linear-lanceolate, sessile and slightly clasping, remotely denticulate, acute, 1' - 3' long, 1"- 3" wide; racemes borne in nearly all the axils, or only in the alternate ones, equalling or longer than the leaves; bractlets much shorter than the filiform spreading pedicels; flowers blue, 2"-3" broad; capsule broader than high, very flat, deeply emarginate at the summit, slightly so at the base, 2"- 2 1/2" broad; seeds flat.
In swamps, Labrador to British Columbia, south to southern New York, Minnesota and California. Also in Europe and Asia. May-Sept.
Veronica officinalis L. Sp. Pl. 11. 1753.
Perennial by stolons, pubescent all over; stem ascending, 3'-10' high. Leaves oblong, oval, or obo-vate, petioled, 1/2'-2' long, obtuse at the apex, serrate, narrowed into the petioles; racemes spike-like, narrow, dense, elongated, often borne only in alternate axils, much longer than the leaves; subulate bract-lets and the calyx longer than the pedicels; flowers pale blue, 2" - 3" broad; capsule obovate-cuneate, compressed, broadly emarginate, 2" high, 1 1/2" broad; seeds numerous, flat.
In dry fields and woods, Nova Scotia to Ontario, South Dakota, North Carolina and Tennessee. Ascends to 5600 ft. in Virginia. Also in Europe and Asia. Appears, in most places, as if introduced. Paul's-betony. Ground-hele. Upland speedwell. May-Aug.
Veronica longifolia L., an erect European species with lanceolate petioled acuminate sharply serrate leaves, has been found in waste grounds and fields from Nova Scotia to New York.