Chaenorhinum rubrifolium subsp. rubrifolium

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 : 226

(a) Subsp. rubrifolium :

Corolla-tube cylindrical, nearly closed at the mouth; spur l-3-5(~4-5) mm, forming an obtuse angle with the tube; seeds with rather prominent, usually more or less tuberculate or spinulose ribs. Throughout the range o f the species.