Veronica filiformis, Sm.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 250

56. V. filiformis Sm. , Trans. Linn. Soc. London 1: 195 (1791).

Procumbent, pubescent perennial, with slender stems up to 50 cm, freely rooting at the nodes, often mat-forming. Leaves 5-10 mm, petiolate, reniform, crenate, mostly opposite on non-flowering stems but alternate on flowering stems. Flowers solitary in leafaxils; pedicels up to 40 mm, often deflexed after flowering. Calyx-segments 3-5 mm, oblanceolate to elliptical, obtuse; corolla 10-15 mm in diameter, pale lilac-blue. Capsule (rarely produced) c. 3 x 4 mm, 2-lobed, with subparallel lobes and rather wide sinus, subglabrous except for long hairs on keel; style c. 3 mm, much exceeding the sinus. Seeds c. 1-5x1 mm, elliptical, shallowly concave on one face. 2/7=14. Damp grassland. Originally cultivated fo r ornament; now widespread as a weed in gardens and lawns, and naturalized among native vegetation in several regions, mainly in N.W. and C. Europe. [Au Be Br Cz D a Ga Ge Hb He Ho Po Rs (K) Su.] (Caucasus andN. Anatolia.)

The frequent sterility of this species is apparently associated with strong self-incompatibility and vigorous growth of single clones.