| 1 | Plant monoecious. Leaves simple, deeply lobed. Male bract conspicuous, inserted below the middle of the flower stalk. — Often cultivated |
| 1' | Plant dioecious. Leaves simple, unlobed or lobed, or 3-foliolate. Male bract either inconspicuous, or conspicuous, inserted at the apex of the flower stalk. — Not or rarely cultivated |
| 2 | Petiole and/or lower blade margin (usually) with conspicuous glands. Plant vigorous. Male perianth c. 50 mm diam. or more |
| 2' | Petiole (and lower blade margin) without glands. Plant more slender. Male perianth less than 50 mm diameter |
| 3 | Leaf blade unlobed, at least c. 1.5 times longer than broad; not or hardly fetid when crushed; green on drying; tertiary venation sharp, with fine areoles. Fruit smooth or partly with sparse slender soft spines |
| 3' | Leaf blade unlobed, or lobed, or 3-foliolate, in outline about as long as wide, always less than 1.5 times longer than broad; fetid when crushed; dull green or brown on drying; tertiary venation coarse. Fruit variously soft-spiny or tubercled (rarely nearly smooth) |
| 4 | Leaf blade 3-foliolate. — Seram, Ambon |
| 4' | Leaf blade simple (unlobed or lobed) |
| 5 | Male flowers solitary on single, axillary peduncle; bract conspicuous, 10-30 mm long. Fruit ornamented (soft spiny or warted, or with lengthwise ribs, or both). Seeds numerous, 10-20, edge shallowly undulate |
| 5' | Male flowers fascicled or in short raceme, the branches (peduncles) slender; bract minute, 1-2 mm long. Fruit ornamented (with few sparse minute spines) or smooth. Seeds few, c. 6, edge with c. 8 conspicuous undulations |
