| 1 | Fruiting specimens |
| 1' | Flowering specimens |
| 2 | Seeds bicoloured, glossy red with a black distal part |
| 2' | Seeds uniformly glossy red |
| 3 | Apex of (at least young and developing) leaflets distinctly acute to acuminate. |
| 3' | Apex of leaflets rounded, truncate, often emarginate |
| 4 | Base of leaflets cuneate; upper surface of leaflets without microscopic pellucid dots |
| 4' | Base of leaflets very broadly rounded to subcordate; upper surface of leaflets with microscopic pellucid dots |
| 5 | Young branches glabrous or with a few scattered glandular hairs. Leaf rachis and pinnae glabrous |
| 5' | Young branches puberulous. Leaf rachis and pinnae puberulous |
| 6 | Seeds asymmetrically oblong or rhomboid in outline; black spot only covering and parallel to the apical margin of the seed, c. 4-5 by 1 mm |
| 6' | Seeds obliquely or regularly obovoid, circular, or ellipsoid in outline, dark spot extending at least 1.5 mm on the face of the seed, not parallel to the apical margin. |
| 7 | Leaflets rigidly chartaceous when dry, primary lateral veins parallel, straight and raised beneath |
| 7' | Leaflets thinly chartaceous or membranous (often somewhat wrinkled when dry), primary lateral veins inconspicuous or hardly visible, arching, not parallel. |
| 8 | Leaflets small, not exceeding 1.5 by 0.7 cm. Pod oblong, straight, valves recurving from the apex at dehiscence |
| 8' | Leaflets larger, (0.8-) 1.4-3.5 by (0.7-)0.9-2 cm. Pod contorted prior to and spirally twisted after dehiscence |
| 9 | Rachis of leaves (15-)20-55 cm. Pod linear falcate, not twisted prior to dehiscence, valves 1.3-1.8 cm broad. Seeds (7-)8-9 by 7-9.5 mm |
| 9' | Rachis of leaves 2.5-21 cm. Pod linear, twisted prior to dehiscence, valves 0.8- 1.2 cm broad. Seeds 4.7-7(-8) by 4.5-7 mm |
| 10 | Pinnae 3-5(-6) pairs, puberulous; leaflets (4-)5-9 on each side of the pinna. Tree to 30 m high |
| 10' | Pinnae 1 or 2 pairs, glabrous; leaflets 2-4 on each side of the pinna. Shrub with slender branches, 1 cm in diameter |
| 11 | Apex of (at least young and developing) leaflets distinctly acute to acuminate (leaflets with prominent, raised, straight, primary lateral veins beneath) |
| 11' | Apex of leaflets rounded, truncate, often emarginate. |
| 12 | Base of leaflets cuneate; upper surface of leaflets without microscopic pellucid dots |
| 12' | Base of leaflets very broadly rounded to subcordate; upper surface of leaflets with microscopic pellucid dots |
