| 1 | Lower leaf surface with persistent dense indumentum; whenever the hairs are short they may be densely interwoven and thus the leaf may seem glabrous. |
| 1' | Lower leaf surface either glabrous, glabrescent, with sparse minute scattered hairs, or with a very minute cobweb-like covering (only visible with a lens). |
| 2 | Twigs l-2.5(-4) mm diam. Leaves 4.5-15 by 1.5-6 cm. Fruits 2.5-3 cm long, with scurfy hairs 0.1-0.2 mm. — Am Is. |
| 2' | Twigs 3-6 mm diam. Leaves 20 cm long or more. Fruits either with distinct hairs, 0.5 -1 mm, or hairs scurfy. |
| 3 | Fruits 4-6.5(-7) cm long, with conspicuous rusty hairs 0.5-1 mm. [Two taxa, with a different distribution, and distinguishable mainly by characters of the male flowers.]. |
| 3' | Fruits 5-8.5 cm long, hairs dull cinnamon, scurfy, 0.1-0.2 mm. — N Moluccas. |
| 4 | Male buds 4.5-6 mm long; bracteole mostly caducous. |
| 4' | Male buds 3-4.5 mm long; bracteole persistent. — Am Is. |
| 5 | Twigs distinctly ridged or winged; myrmecophilous. [Fruits subsessile, more or less ovoid, 2 cm long, apiculate, minutely tomentulose.] —Kai Is. |
| 5' | Twigs neither ridged nor winged; not myrmecophilous. |
| 6 | Plants conspicuously glabrous. Flowers not known. — Seram. |
| 6' | Indumentum present on terminal leaf bud, twig, and flowers. |
| 7 | Leaves 6-17(-25) cm long, lower surface with scattered dots and dashes. — Am Is. |
| 7' | Leaves of various sizes, without dots and dashes. |
| 8 | Female buds much narrowed towards the acute apex, the apical part sharp-angular in cross section. Leaves to 30 cm long. |
| 8' | Apex of female buds narrowed or not, in cross section circular or at most bluntly angular, but not sharply angular. Leaves small or large, to 40 cm long. |
| 9 | Buds 5-6 mm long. Leaves below glabrous or with minute scattered hairs. Fruits 3-3.5 cm long, with scattered hairs 0.3-0.5 mm, or glabrescent. — N Moluccas (Sula Is., Bacan, Bum). |
| 9' | Buds 10 mm long. Leaves below with dense or scattered scale-like hairs 0.1-0.2 mm. Fruits 5-6 cm long, densely dark brown short-pubescent, hairs 0.2-0.3 mm. — N Moluccas. |
| 10 | Twigs 3-5(-10) mm diam. Leaves 25-45 cm long. |
| 10' | Twigs 1-5 mm diam. Leaves mostly less than 30 cm long (up to 43 cm long in M. nivea). [Fruits 2-5.5 cm long, pubescent, or fruits larger but then glabrous or early glabresent.]. |
| 11 | Twigs 4-7(-10) mm diam.; bark of twigs conspicuously longitudinally cracking, ± flaking. Lower leaf surface papillose (lens!). [Fruits large, (4-)5-8 cm long, with persistent scurfy hairs 0.1-0.2 mm.] — N Moluccas (Bacan). |
| 11' | Twigs 5-10 mm diam.; bark of twigs striate, at most finely cracking and finely flaking. Lower leaf surface not papillose. [Female flowers and fruits not known.]— N Moluccas (Bacan). |
| 12 | Fruits glabrous or largely early glabrescent, hairs 0.1 mm or less. Inflorescences delicate, few-flowered, without or with a slender peduncle. [Leaves elliptic, with few lateral nerves per side.]. |
| 12' | Fruits with persistent indumentum, hairs may be very short and inconspicuous. Inflorescences with or without a peduncle, with the flowers in a woody scar-covered short-shoot. |
| 13 | Twigs 2-3.5 mm diam. Leaves ± coriaceous, 9-22 cm long, below late glabrescent. Fruits 4.5-8 cm long. — N Moluccas. |
| 13' | Twigs 1-2 mm diam. Leaves chartaceous, 6-13 cm long, below early glabrescent. Fruits 4-6 cm long. — Cultivated (origin Banda). |
| 14 | Leaves pale below, with scattered dark-coloured small dots, representing hair scars (lens!). — Known in the Moluccas only from a sterile collection from Talaud Is. |
| 14' | Leaves not conspicuously pale below, without scattered dots. |
| 15 | Fruits 3-4 cm long, with conspicuous coarse hairs, (0.5-)l mm. |
| 15' | Fruits variable in size, hairs mealy, scurfy, or woolly, shorter, 0.1-0.5(-0.8) mm long. |
| 16 | Lower leaf surface greyish or whitish, glabrescent, indumentum weak, its stoutest hairs leaving numerous regularly spaced, small, dark dot-like scars (lens!). Fruits short-ellipsoid, 3-4.2 cm long, hairs 0.1-0.5 mm; pericarp thick and woody, 5 mm thick. — N & C Moluccas. |
| 16' | Upper and lower leaf surface more concolorous, or, whenever greyish or whitish, without small dots. |
| 17 | Leaves elliptic to oblong-lanceolate, 14-35 cm long. Fruits ellipsoid, (2.5-)3-3.5 (-4.5) cm long, hairs 0.1-0.2 mm. |
| 17' | Leaves generally smaller, elliptic to lanceolate, to 20 cm long. Fruits variable 18 18a. Lower leaf surface not papillose (lens!). Fruits subglobose, 2.5-3 cm long; pericarp 4-8 mm thick, hairs 0.1 mm or less. — N Moluccas. |
| 17'' | Lower leaf surface papillose. Fruits ellipsoid; pericarp 1-5 mm thick, hairs short or long, 0.1-1 mm. [Four taxa, difficult to segregate without male flowers.]. |
| 18 | Male inflorescences (short) pedunculate; male buds 2.5 mm long. [Fruits ovoid-ellipsoid, 3-4 cm long, with scurfy hairs 0.2 mm.] — N Moluccas (Sula Is., Halmahera, Obi). |
| 18' | Male inflorescences (sub)sessile; male buds 3-6 mm long. |
| 19 | Leaves membranous. [Venation on lower leaf surface distinct. Fruits 2-3.5 cm long, hairs 0.1(-0.2) mm.] Male buds small, 3 mm long — NE Moluccas. |
| 19' | Leaves chartaceous. Male buds 4-6 mm long. |
| 20 | Venation on lower leaf surface generally indistinct; lateral nerves 8-20 per side, rather dense; blade 4-17 cm long. Fruits 1.3—2.6(—3) cm long, hairs 0.1 mm. |
| 20' | Venation distinct or not; lateral nerves more lax, 6-12 per side; blade 7-24 cm long. Fruits 2.5-3.5(-3.8) cm long, hairs 0.3-1 mm. — SE Moluccas (Tanimbar Is). |
