Acanthus 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 : 283

1. Acanthus L. 2

Robust perennial herbs or small shrubs. Stems simple, terete, erect. Leaves mostly basal, pinnatifid to pinnatisect. Flowers in dense, terminal, cylindrical spikes. Bracts large, spinose-dentate; bracteoles entire, lanceolate to linear. Calyx 4-lobed; upper and lower lobes large, the lateral small. Corolla 1-lipped (upper lip absent), 3-lobed; tube short. Stamens 4, included; anthers 1 -celled, connate in pairs. Fruit a capsule. 1 Basal leaves spinose-dentate 3. spinosus 1 Basal leaves not spinose-dentate 2 Leaf-lobes not narrowed at base; lower lip of calyx glabrous at apex 1. mollis 2 Leaf-lobes narrowed at base; lower lip of calyx pubescent at apex 2. balcanicus