'There is indeed so much conformity in the structure of their [Lonchocarpus, Derris, Pongamia, Piscidia, Muellera] flowers and in the general plan of their pods, that I should have had no hesitation in uniting them all into one large genus divided artificially into sections, were it not for the inconvenience, already alluded to, of suppressing long-established and universally recognized genera, when they can be marked out by a tolerably positive character, however artificial and isolated that character may be.' Bentham (i86o: 19) The weight of convention which persuaded Bentham a hundred years ago to retain genera of convenience in this group persists. The reappraisal of illconforming elements presents a continuing problem of whether to weaken already tenuous distinctions, segregate further small genera or make piecemeal transfers to redefined concepts. Mendonga & Sousa (1965) have recently re-segregated the monotypic African genus Capassa Klotzsch for the species more familiarly known as Lonchocarpus capassa Rolfe. Capassa is 'lonchocarpoid' in general facies, but has a distinct wing to the adaxial suture of the fruit. The absence of such a wing is technically the one character which distinguishes Lonchocarpus Kunth from Derris Lour. The species was indeed transferred to Derris by Harms (1902, 1915), but looks so unlike any other species of that genus that inclusion there has not otherwise been considered acceptable. In trying to determine the generic position of this species for the 'Flora of Tropical East Africa', I have noticed that Lonchocarpus capassa is not the only species which threatens the tenuous distinction between Derris and Lonchocarpus, that in the sum of its characters it seems to fall naturally into the distinctive Afro-Madagascan section Paniculati Benth. of Lonchocarpus, and that new generic criteria emerge if certain more obviously extraneous elements are extricated from the complex. I propose to transfer Lonchocarpus section Caudaria Dunn back to Millettia Wight & Arn., transfer the Australian species of Lonchocarpus to Kunstleria Prain and restitute Derris section Aganope (Miq.) Benth. to generic level, including in it Ostryoderris Dunn. With these excisions, Lonchocarpus section Paniculati (including Lonchocarpus capassa) may be easily distinguished from Derris by the thyrsoid panicles, the flowers not fascicled or densely crowded on contracted ultimate branches of the inflorescence. The basic problem of delineating genera in this group remains nonetheless, and I attempt only a provisional patching up of