Verbena bonariensis, L.

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 : 123

2. V. bonariensis L. , Sp. Pl. 20 (1753) .

Perennial with stiff, erect, little-branched stems up to 200 cm, scabrid on the angles. Leaves 7-13 x 1-2-5 cm, oblong-lanceolate, regularly inciseserrate, rugose, scabrid and more or less villous, tomentose beneath, sessile, amplexicaul. Panicle terminal, composed of several long-pedunculate cymes, each cyme of dense, subcylindrical, sessile spikes up to 2 cm in fruit; bracts equalling or shorter than calyx, concave, lanceolate-acuminate, usually dark blue; corolla blue, twice as long as calyx. Roadsides and gravelly waste places. Naturalized in W. Europe. [Az?Be?Ga Lu.] ( Argentina and S. Brazil.)