Sium L.

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 : 333

27. Sium L. 1

Submerged leaves 2- to 3-pinnate, with linear lobes; aerial leaves usually pinnate, with broad lobes. Sepals present, sometimes very small. Petals white, obcordate; apex inflexed. Fruit ovoid or ovoid-oblong, slightly compressed laterally. Ridges slender or broad, the lateral marginal on the mericarps; vittae 1-3, superficial; stylopodium nearly flat.

Stem strongly furrowed; sepals conspicuous, lanceolate 1. latifolium Stem striate; sepals very small 2. sisarum