Sesbania sect. Sesbania.

Agati Adanson, Fam. pl. 2: 326. 1763. Sesbania subg. Agati (Adanson) Baker in J. D. Hooker, Fl. Brit. Ind. 2: 115. 1876. TYPE: Agati grandiflora (L.) Desvaux [5 Sesbania grandiflora (L.) Poiret].

Resupinaria Rafinesque, Sylva tell. 115. 1838. TYPE: Resupinaria (L.) Rafinesque [5 Sesbania grandiflora (L.) Poiret].

Darwinia Rafinesque, Fl. ludov. 106. 1817, non Darwinia Rudge, 1815 [Myrtaceae]. Monoplectra Rafinesque, Fl. ludov. 106. 1817, pro. syn. TYPE: Darwinia exaltata Rafinesque [5 Sesbania herbacea (Mill.) McVaugh].

Sesbania subgenus Pterosesbania Gillett, Kew Bull. 17: 149. 1963. TYPE: Sesbania tetraptera Hochst. ex Baker.

We recircumscribe the pantropical S. sect. Sesbania to include former S. subg. Agati and S. subg. Pterosesbania, which comprises two species mainly from southern Africa, S. tetraptera and S. rogersii Phill. & Hutch., the latter of which is now considered a subspecies of S. tetraptera (Lewis 1988). These two species (or subspecies) produce mature legumes that are very similar to those of S. sect. Daubentonia (DC.) Benth. in that they have legumes with four longitudinal wings along the legume body. This shared similarity in legume morphology prompted Lavin and Sousa S. (1995) to synonymize S. subg. Pterosesbania under S. sect. Daubentonia. Results of our phylogenetic analysis strongly suggest that the four-winged legume was independently evolved in the New World sect. Daubentonia and the African S. tetraptera (including S. rogersii). However, S. subg. Pterosesbania have generally long, many-seeded linear fruits, which are characteristic of the species of S. sect. Sesbania.