| 1 | Male perianth 4-6 mm long; androecium shorter than the perianth tube. Young twigs and inflorescences with woolly hairs l(-2) mm long; lower leaf surface with persistent woolly hairs 0.5 mm long. Leaves 18-42 cm long, petiole 3-5 mm thick. Fruits 2.5-3.5 cm long, with hairs 0.3-0.5 mm. — Peninsular Malaysia, Sumatra, Borneo |
| 1' | Male perianth 2-5 mm; androecium as long as the perianth tube. Young twigs and inflorescences glabrescent, or with hairs less than 0.5 mm; lower leaf surface glabrescent or with appressed hairs, indumentum less than 0.5 mm high. Leaf size variable, petiole 1-3 mm diameter. Fruits 2-3 cm long, pubescent or glabrescent. |
| 2 | Young twigs with ± woolly hairs to 0.5 mm long. Leaves densely pubescent below. Fruits 2.3-3 by 2-2.2 cm, indumentum conspicuous, pericarp 3-5 mm thick. — Central Sulawesi |
| 2' | Young twigs glabrescent or variously pubescent by appressed hairs, less than 0.2 mm long. Leaves below glabrescent or with ± scattered hairs. Fruits generally smaller, glabrescent or pubescent, pericarp up to 2 mm thick |
| 3 | Twigs, including the apical part, conspicuously densely set with lenticels. Lower leaf surface with brownish hairs. Midrib flat above; nerves at c. 45° to the midrib in the middle of the leaf. Fruits ellipsoid-ovate with truncate base, 2 cm long, short-pubescent. — Borneo |
| 3' | Twigs towards the apex without or with but a few lenticels. Lower leaf surface glabrescent or with scattered, inconspicuous, greyish or pale brown hairs. Nerves at more than 45° to the midrib. Fruits globose to ellipsoid-oblong, base not truncate, 1.8-2.8 cm long, glabrescent or pubescent |
| 4 | Twigs at apex 1-2 mm, about 10 cm lower down 2-3.5 mm diameter. Leaves 5-17 (-27) by 1.5—5.5(—8.5) cm; midrib flat or sunken above. — W & E Malesia (in E Malesia not rarely twigs thicker and leaves larger) |
| 4' | Twigs at apex (2-)2.5-4 mm, about 10 cm lower down (3-)3.5-5.5 mm diameter. Leaves larger, 14-33 by (5.5—)6—13 cm; midrib usually sunken |
| 5 | Lateral nerves on lower leaf surface distinct but little prominent, at 60-70° to the midrib in the middle of the leaf; blade drying flat. Anthers 6(-8), straight. — Borneo |
| 5' | Lateral nerves on lower leaf surface very dinstinct and prominent, at (35-)40-50 (-55)° to the midrib in the middle of the leaf; blade generally drying irregularly undulate. Anthers 6-10, sometimes twisted. — S Thailand, W Malesia. |
