Digitalis purpurea subsp. purpurea

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 : 240

(a) Subsp. purpurea :

Lower leaves lanceolate to ovate, gradually tapered to the petiole, glabrous to tomentose ( var. tomentosa (Hoffmanns. & Link) Brot. ), greenish to whitish. Pedicels usually equalling or shorter than calyx. Corolla purple (rarely pink or white), glabrous or pubescent outside. In = 56. Almost throughout the range o f the species. Extremely variable in height, indumentum, size and shape of leaves and bracts, pedicels, calyx, colour and spotting of the corolla. Some local populations show characteristic combinations of these variable characters, but the pattern of variation is too complex and fluctuating to enable them to be treated as subspecies. Dwarf alpine ecotypes also occur. Superimposed on this local variation there is a regional differentiation between the populations of the Iberian peninsula and of the rest of Europe in habit, details of indumentum, branching of inflorescence and seed-colour.