| 1 | Venation laxly reticulate, prominent on both sides of the leaflet |
| 1' | Venation on the upper side of the leaflets minutely reticulate, often inconspicuous to hardly visible |
| 2 | Slender. Twigs 0.25-1 cm in diam. Leaves 1-5(-8)-jugate. Leaflets linear or elliptic, up to 20 cm long, 2.5-8.5 cm broad. Continental Asia, Malay Peninsula, Sumatra |
| 2' | Robust. Twigs up to 1.5 cm in diam. Leaves 4-9-jugate. Leaflets linear, 10-35 by 5-10 cm. Borneo, Palawan |
| 3 | Leaflets elliptic, not or sometimes slightly acuminate; nerves above prominulous to flat; intercalated veins hardly conspicuous. Continental Asia, Malay Peninsula |
| 3' | Leaflets linear with a long and slender acumen; nerves above sunken; intercalated veins well developed. Malay Peninsula, Sumatra |
| 4 | Leaflets beneath rather densely ± patently hairy, especially on the veins, in between glabrous or sometimes sparsely patently or loosely appressedly hairy, the indumentum thus emphasizing the venation |
| 4' | Leaflets beneath between the nerves either minutely sericeous, the indumentum obscuring the venation, or ± glabrous |
| 5 | Twigs and leaf axes hairy. Largest leaflets 20-35 cm long, up to 5 times as long as wide; nervation not conspicuously dense, nerves in the central part of the leaflets 0.5-2 mm apart. Malay Peninsula, Sumatra, Borneo |
| 5' | Twigs and leaf axes early glabrescent. Leaflets up to 17 cm long, 2-2.5 times as long as wide; nervation dense, nerves in the central part of the leaflets 0.5-0.75 mm apart. Borneo |
| 6 | Petiole terete nearly to the base. Leaflets flexible pergamentaceous or papyraceous when dried, apex distinctly, mostly long, slender, acute acuminate |
| 6' | Petiole strongly flattened at base. Leaflets stiff- pergamentaceous, apex obtuse to rounded hardly acuminate. Malay Peninsula, Sumatra |
| 7 | Leaflets linear with parallel sides, beneath gla brous or early glabrescent. Twigs and leaves soon glabrous (Borneo) or hairy (Malay Peninsula, Sumatra) (var. cuspidatum) |
| 7' | Leaflets elliptic with gradually curved sides, beneath ± sericeous. Twigs, leaf axes, and midrib beneath densely hairy. Borneo |
| 8 | Fruit appendages straight, upper part 2-4 mm long. Borneo |
| 8' | Fruit appendages curved, upper part c. 8-10 mm long. Malaya |
