Perfoliata

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 346

Sect. Bupleurum (Sect. Perfoliata Godron ). Annual. Lower leaves sessile or shortly petiolate; upper perfoliate; veins numerous, slender, radiating, anastomosing near the margin and connected by fine cross-veins elsewhere. Bracts absent; bracteoles 4-7, lanceolate to ovate, longer than the partial umbel.