1 | Inflorescence usually a median triad or pentad developing from the apical bud of the shoot (Bismarck Archipelago & Karkar Island, Papua New Guinea); section Leiospermum |
1' | Inflorescence composed of 1-3 pairs of dyads or tetrads inserted in the opposite axils of the most distal pair of leaves and sometimes in axils of subdistal leaves; apical bud of shoot, between central peduncles of the partial inflorescences, present and usually dormant, rarely developing vegetatively during reproduction (throughout Malesia); section Fasciculatae |
2 | Flowers inserted on the inflorescence axes singly, each individual pedicel subtended by a bract; leaves simple |
2' | Flowers inserted on the inflorescence axes in fascicles, each fascicle subtended by a bract; leaves usually imparipinnate, less often simple or trifoliolate |
3 | Leaves simple or trifoliolate, the blades 4-9.5 by 1.7-4.4 cm, glabrous (Philippines, Sulawesi) |
3' | Leaves imparipinnate, lateral leaflets in 1-19 pairs, only occasional leaves trifoliolate or if regularly trifoliolate, then leaflets smaller and densely hirsute (W. cf. pullei, New Guinea) |
4 | Leaflets small, the largest laterals 0.6-3.2 by 0.2-1.5 cm, often in numerous pairs (2-19) |
4' | Leaflets medium-sized, the largest laterals 2.4-10 by 0.6-3.7 cm, usually in fewer pairs (1-8) |
5 | Leaflets bullate and carinate, the margins strongly recurved and revolute (Mt Kinabalu) |
5' | Leaflets flat or if slightly bullate then the margins not rolled back |
6 | Petiole and rachis segments narrowly winged and leaflets numerous, 3-20 pairs; stems and leaflets glabrous |
6' | Petiole and rachis segments terete or semiterete, or if narrowly winged then leaflets fewer, 1-6 pairs; young stems and young leaflets tomentose, velutinous or sericeous, sometimes glabrescent |
7 | Leaflets inserted at almost 90° to rachis, and secondary veins at almost 90° to midrib. |
7' | Leaflets inserted at an acute acroscopic angle and secondary veins at an acute acro-scopic angle to midrib |
8 | Lateral leaflets obovate or oblanceolate (New Guinea) |
8' | Lateral leaflets oblong to narrowly ovate (Peninsular Malaysia) |
9 | Indumentum on young twigs pilose and on leaves pilose and pubescent |
9' | Indumentum on young twigs and leaves absent or pubescent to villous-tomentose, not pilose |
10 | Terminal leaflet markedly rhomboidal and distinctly larger than the largest laterals. |
10' | Terminal leaflet narrowly elliptic, only slightly larger than the largest laterals |
11 | Lateral leaflets usually in 5-7 pairs, the largest 2-6.5 by 0.6-1.4 cm, decreasing in size proximally along the rachis; margin of stipules often wavy or coarsely toothed (Philippines) |
11' | Lateral leaflets in 3-6 pairs, the largest 3-5 by 1-1.6 cm, not markedly decreasing in size proximally; margin of stipules entire (N Sulawesi) |
12 | Leaflets drying grey or dark chestnut above and chestnut beneath, lateral ones in 1-4 pairs, the largest 2.4-7 by 0.6-1.9 cm; petiole and rachis sometimes narrow- ly winged |
12' | Leaflets drying dark green or brown but not chestnut, lateral ones in 1-8 pairs, the largest 4.2-10 by 1.4-3.5 cm; petiole and rachis not winged |
13 | Underside of leaflets bearing short scurfy hairs; indumentum on growing tips, stipules, leaf rachises and inflorescence axes dense rusty or golden brown villous-tomentose; lateral leaflets elliptic to obovate, the base ± symmetrical and the apex rounded or obtuse |
13' | Underside of leaflets glabrous; indumentum on growing tips, stipules, leaf rachises and inflorescence axes puberulent to tomentose or absent, not rusty or golden brown; lateral leaflets lanceolate to elliptic or ovate, the base usually asymmetrical and the apex usually acute or acuminate |
14 | Lateral leaflets lanceolate, narrowly elliptic to ovate, in 1-8 pairs |
14' | Lateral leaflets narrowly to broadly elliptic, not broader towards to base, in 2-3 pairs |
15 | Pedicels 1.5-3 mm long (widespread in Malesia except Sulawesi and the Philippines) |
15' | Pedicels very short, 0.2-0.5 mm (Sulawesi) |
16 | Lateral leaflets attenuate into a petiolule at base, often conduplicate, 5-8.5 by 2-3.7 cm |
16' | Lateral leaflets acute at base, ± sessile, not conduplicate, 4.8-6.4 by 1.4-2.1 cm. |