Cal deeply 4-parted in our spp. (5-parted in some no. 12 [Veronica officinalis L.]), the lobes equal or the upper shorter; cor-tube much shorter than the lobes (except in no. 1 [Veronica longifolia L.]), the limb rotate, obscurely 2-lipped, 4-lobed by fusion of the upper 2; stamens 2 (the upper pair), inserted at the orifice of the cor; pollen-sacs parallel; style exsert; stigma 1; fr short, often flattened, loculicidal and sometimes also septicidal, subtended by the sep and tipped by the persistent style; herbs with opposite (rarely whorled) foliage-lvs, the bracteal lvs mostly alternate or scattered; fls small, white to blue or purple. 300, N. Temp., especially Old World.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.