Senecio rivularis subsp. rivularis

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1976, Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae), Cambridge University Press : 200

(a) Subsp. rivularis (inch S. crispatus DC. ): Basal leaves with broadly winged petiole, often undulate-crispate at the margin. Capitula 5-15. Achenes glabrous; pappus at anthesis about as long as corolla-tube. Throughout most of the range of the species.