Erysimum cheiranthoides subsp. cheiranthoides

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 275

(a) Subsp. cheiranthoides :

Annual, usually 20-50 cm, sparsely pubescent; base of the stem 2-6 mm in diameter, with 5-10 internodes between the basal rosette and the inflorescence; cauline leaves acute or subacute, widest at the middle, erecto-patent. 2n= 16. Throughout the range o f species except the extreme north.