| 1 | Male inflorescences branched, with a smooth main peduncle sometimes subsessile, slender, simple or branched; inflorescences lasting one or a few flowering seasons only. |
| 1' | Inflorescences (sub)sessile densely scar-covered simple or 2-4-furcate thickish woody short-shoots, lasting several flowering seasons, each season producing a number of new flowers at the apex; peduncle (non scar-covered part) absent or up to 2 mm long. |
| 2 | Plant wholly conspicuously glabrous. [Male flowers not known.] — Seram. |
| 2' | Indumentum obvious on terminal leaf bud. |
| 3 | Buds narrow, 6-8 by 2-3 mm, the apical part markedly angular, apex (sub)acute. — N Moluccas (Sula Is., Bacan, Bum). 123b. M. simiarum subsp. celebica b. Buds variable, not angular, apex rounded. |
| 4 | Buds 3-4.5(-5) mm long, [rough-pubescent. Nerves on upper leaf surface flat or impressed, lower leaf surface papillose.] — N Moluccas. |
| 4' | Buds 5-11 mm long. |
| 5 | Buds conspicuously pubescent. Leaves large, 25-45 cm long, lateral nerves 25-30 per side, impressed above. Bark of older twigs longitudinally cracked. — N Moluccas (Bacan). |
| 5' | Buds either glabrous, glabrescent, or short-haired. Leaves smaller, 6-22 cm long, lateral nerves fewer, above flat or but little impressed. |
| 6 | Pedicel 1 mm thick. Flowers thinly pubescent. Leaves subcoriaceous, 9-22 cm long, lower surface with minute indumentum, late glabrescent. Twigs 2-3.5 mm diam. — N Moluccas. |
| 6' | Pedicel less than 1 mm thick. Flowers glabrescent with sparse, very minute indumentum. Leaves chartaceous, 6-13 cm long, early glabrescent. Twigs 1-2 mm diam. — Origin Banda; known only from cultivated specimens. |
| 7 | Buds (10-)13-15 mm long. |
| 7' | Buds less than 10 mm long. |
| 8 | Twigs ridged or winged; inhabited by ants. — SE Moluccas (Kai Is.) and New Guinea. |
| 8' | Twigs not winged. — N Moluccas (Obi, Halmahera). |
| 9 | Twigs 4-7(-10) mm diam. Leaves (15-) 17-40 cm long. |
| 9' | Twigs 1-4(-5) mm diam. (4-5 mm in some material of M. fatua and M. inutilis). Leaves generally much shorter than 40 cm (15-40 cm in M. nived). |
| 10 | Lower leaf surface early glabrescent or with scattered, minute, scale-like hairs less than 0.1 mm (lens!). [Male buds 8-8.5 mm long.] — N Moluccas (Bacan). |
| 10' | Lower leaf surface densely tomentose (hairs may be minute). [Two species, distinguishable mainly by fruit characters.]. |
| 11 | Buds 6 mm long. — N Moluccas. |
| 11' | Buds 4-6 mm long. — Moluccas (and Sulawesi, Philippines). |
| 12 | Lower leaf surface densely and persistently pubescent, the hairs may be short and scale-like (lens!). |
| 12' | Lower leaf surface glabrous, early glabrescent, or with minute scattered hairs |
| 13 | Twigs (2.5-)4-5 mm diam. Leaves 20 cm long or more. Buds 4-6 mm long. |
| 13' | Twigs 1-2 mm diam. Leaves 15 cm long or less. Buds 2-2.5 mm long. — Am Is. |
| 14 | Bracteole caducous; buds 4.5-6 mm long. |
| 14' | Bracteole persistent; buds 3-4.5 mm long. — Am Is. |
| 15 | Lower leaf surface with scattered dark brown dots and dashes (lens!). — Am Is. |
| 15' | Leaves without larger dots; small dots present or absent. |
| 16 | Leaves pale below, with minute dots representing hair scars. — Known in the Moluccas only from one sterile collection from Talaud Is. |
| 16' | Lower leaf surface not conspicuously pale, without dark dots (lens!). |
| 17 | Buds cylindrical, narrow; androphore about as long as the synandrium. |
| 17' | Buds ovoid or ellipsoid(-oblong); androphore about as long as or shorter than the synandrium, mostly pubescent, at least at base. [Lateral nerves not particularlydense.]. |
| 18 | Androphore glabrous. |
| 18' | Androphore densely pubescent. [Buds small, 3.5-4 mm long. Leaves pale below.] — N Moluccas (Bacan, Obi, Bum). |
| 19 | Leaves membranous; venation distinct below. Buds 2.5-3 mm long. — NE Moluccas. |
| 19' | Leaves chartaceous; venation faint below. Buds 4-6 mm long. |
| 20 | Buds 2.5 mm long. — N Moluccas (Sula Is., Halmahera, Obi). |
| 20' | Buds more than 3 mm long. |
| 21 | Twigs 2-2.5 mm diam. or more. |
| 21' | Twigs l-2(-2.5) mm diam. |
| 22 | Perianth with hairs 0.1 mm. Pedicel about as long as the perianth. — N Moluccas. |
| 22' | Perianth with hairs 0.2-0.5 mm. Pedicel usually shorter than the perianth. |
| 23 | Buds cleft about 1/3 to nearly halfway. Inflorescences sessile or pedunculate. — N Moluccas. |
| 23' | Buds cleft c. 1/4. Inflorescences sessile. — SE Moluccas (Tanimbar). |
