KEY TO THE SPECIES

1Inflorescence composed of racemosely arranged, pedunculate spikes, aggregated into umbels and these in panicles. Calyx up to 5 mm long. Pods with a thinly woody epicarp and a parchmentlike endocarp (Subg. Minahassae)
1'Inflorescence composed of racemosely or ± corymbiform arranged pedunculate racemes. Calyx 7 mm long or more. Pods with a thin and flaking epicarp and a woody endocarp (Subg. Serianthes)
2Calyx and corolla with yellowish brown indument. Corolla-tube usually not projecting beyond the calyx. Pod swollen over the seeds; valves with hardly branched main veins. Main vein of leaflets strongly diagonal for more than the central third of the leaflet
2'Calyx with rusty brown indument, darker than the corolla. Corolla-tube projecting beyond the calyx. Pod not swollen over the seeds; valves with branched main vein. Main vein of leaflets diagonal across about the central third of the leaflet
3Pinnae c. 20 pairs per leaf; leaflets (10—)12—15(—16) mm long. Corolla 27-36 mm long. Pod 6-6.5 cm wide
3'Pinnae 6-10(-ll) pairs per leaf; leaflets (7-)9-17(-23) mm long. Corolla 24-29 mm long. Pod 4.5-6 cm wide