Sp. Pl. 1: 13. 1753.
Perennials. Stems ascending, rarely erect, (7–)10–30(–50) cm, densely eglandular-hairy, hairs along stem in 2 prominent lines. Leaves: blade narrowly ovate to ovate-orbiculate, (10–)12–30(–42) × (6–)10–22(–30) mm, 1–2 times as long as wide, base truncate to ± cordate, margins crenate to deeply incised, apex obtuse, surfaces variably hairy. Racemes 1–4, axillary, 40–100(–200) mm, 15–40(–60)-flowered, axis eglandular-hairy, sometimes also glandular-hairy; bracts linear-elliptic, 3–7 mm. Pedicels suberect, (3–)5–8(–10) mm, equal to or shorter than subtending bract, eglandular- and glandular-hairy. Flowers: calyx 4-lobed, lobes 2–8 mm, apex acute, eglandular- and, sometimes, glandular-hairy; corolla blue obscure darker nerves and sometimes whitish margin, (6–)10–14(–17) mm diam.; stamens 4.5–6.5 mm; style (2.5–)4–5 mm. Capsules strongly compressed in cross section, obcordiform to obdeltoid, (2–)3.5–4(–5) × (3.5–)4–5(–5.5) mm, apex ± emarginate, eglandular-hairy. Seeds (2–)12–20(–28), yellow, ellipsoid, flat, 1.1–1.7 × 0.6–1.5 mm, 0.2–0.4 mm thick, smooth to subrugose. 2n = 16, 32 (Eurasia).
Phenology: Flowering Apr–Jun(–Oct).
Habitat: Rich soils, deciduous forests, forest edges, roadsides, chaparral, scrub, meadows, lawns.
Elevation: 0–2200 m.
Alta., B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Alaska, Conn., D.C., Idaho, Ill., Ind., Maine, Md., Mass., Mich., Mo., Mont., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Vt., Va., Wash., W.Va., Wis., Eurasia, introduced in South America (Argentina).
The description provided here for Veronica chamaedrys is solely for the tetraploid cytotype, most probably the exclusive cytotype in the flora area and in central and western Europe. The diploid cytotype is so far only known from eastern and southeastern Europe (K. E. Bardy et al. 2010). A significant change in morphology can occur in shaded habitats, in which especially the petiole can be elongated beyond the range given.
It is unclear whether Veronica chamaedrys is introduced throughout the flora area; it may be native in northeastern areas of North America.