| 1 | Trichilia absent. |
| 1' | Trichilia present. |
| 2 | Stipules normally 15-35 cm long; uncinate and curved hairs lacking: leafv twigs normally 4-10 cm thick. |
| 2' | Stipules at most 15 cm long, if up to 20 cm long, then uncinate and/or curved hairs present at least on the branchlets and/or the main veins of the blade beneath; leafy twigs normally up to 5 cm thick. |
| 3 | Blade with 12-15 incisions; free part of the midsegment with ca. 2x 40-45 secondary veins. |
| 3' | Blade with 8-11 incisions; free part or the midsegment with 10-20 secondary vein pairs. |
| 4 | Trichilia with 5-9 mm long, white hairs. |
| 4' | Trichilia without such hairs. |
| 5 | Secondary veins loop-connected in the leaf margin. |
| 5' | Secondary veins loop-connected just inside the leaf margin. |
| 6 | Stipules subpersistent; peduncle of the pistillate inflorescence 20-25 cm long; staminate inflorescences with 4-6(-11) spikes, 0.8-1.8 cm in diam.: anthers at least 1 mm long. |
| 6' | Stipules caducous; peduncle of the pistillate inflorescence at most 16 cm long; staminate inflorescence with (usually) at least 12 spikes 0.2-0.4 cm in diam.; anthers ca. 0.5 mm long. |
| 7 | Blade with incisions usually reaching midway between margin and petiole; stipules usually not arachnoid-hairy; upper part of the perianth of the pistillate flower not arachnoid-hairy; stigma penicillate; staminate inflorescences with (15-)30-40 spikes, ca. 0.2 cm in diam.; in periodicallv inundated places. |
| 7' | Blade with incisions usually deeper than midway between margin and petiole; stipules usually arachnoid-hairy; upper part of the perianth of the pistillate flower arachnoid-hairy; stigma peltate; staminate inflorescences with (4-)12-25(-30) spikes, ca. 0.3 cm in diam.; in non-inundated places. |
| 8 | Petiole (and usually also the upper surface of the blade) densely white arachnoid-hairy; upper part of the perianth usually muriculate: soathe without or with sparse arachnoid hairs. |
| 8' | Petiole (and usually also the upper surface of the blade) not white arachnoid- hairy, or, if so, then the upper part of the perianth of the pistillate flower white arachnoid-hairy and the upper part of the perianth of the staminate flower smooth and glabrous; spathe with more or less dense white arachnoid hairs. |
| 9 | Blade on the main veins predominantly hirtellous beneath; upper part of the perianth of the pistillate flower with arachnoid indument to near the aperture; peduncle and spathe of the staminate inflorescence normally up to 10 cm long. |
| 9' | Blade on the main veins predominantly minutely puberulous beneath; upper part of the perianth of the pistillate flower without arachnoid indument; peduncle and spathe of the staminate flower normally over 10 cm long. |
