| 1 | Inflorescence capitiform, axillary, consisting of 1-3-flowered dichasial clusters. ♂ Flowers with 10-20 stamens; anthers linear, 2-7 mm long, basifixed, apiculate; pollen grains peroblate, 4-9-colpate, exine distinctly echinulate. ♀ Flowers dimerous, perianth poorely developed, styles 2, short, tongue-shaped; stigmas papillose, covering the inner surface of the styles; ovary 2-celled, flattened. Leaves glandular-dotted; stipules peltately attached, their insertion surrounded by colleters |
| 1' | Inflorescence a spike of condensed cymes, flowers solitary or in dichasial clusters of 3-30 along the rachis. ♂ Flower with 6-12 stamens; anthers 0.25-1 mm long, non-apiculate; pollen grains prolate or perprolate, 3-colpate, 3-colporate, exine scabrate or more or less smooth. ♀ Flowers 3(-6)-merous; perianth well-developed; styles 3-6 (-9), conical or terete; stigmas terminal, punctiform or capitate; ovary 3(-6)-celled, not flattened. Leaves not glandular-dotted; stipules basally inserted; no colleters. |
| 2 | ♂ Flowers with the pistillode always present; stamens 10-12, anthers 0.25-0.35 mm long, dorsifixed; pollen grains perprolate (ellipsoidal), c. 16 by 10μ, exine more or less smooth. ♀ Flowers with 10-12 staminodes; stigmas punctiform. ♂ Inflorescence always erect. |
| 2' | ♂ Flower without pistillode, stamens 5-6(-9), anthers ½-1 mm long, basifixed; pollen grains prolate (spheroidal), 30-40 by 20 μ, exine scabrate. ♀ Flower without staminodes or rarely with 5-6 staminodes; stigmas capitate. ♂ Inflorescence pendulous or erect. |
| 3 | Cupule-primordia already developed before anthesis, always solitary, with distinct vertical sutures, with 2-4(-8) separate growing-points; enclosing 1-3(-7) ♀ flowers |
| 3' | Cupule-primordia not yet developed before anthesis, solitary or in dichasial clusters, ring-shaped without vertical sutures and separate growing-points; enclosing 1 ♀ flower only. |
| 4 | Inflorescence always unisexual, simple. ♂ Inflorescence pendulous. ♀ Flowers always solitary, staminodes sometimes present; ovary rounded in cross-section. Terminal buds conferted, the scales with a tendency towards orthostichy. Leaves spirally arranged, crowded at the end of the twigs; stipules not interpetiolar |
| 4' | Inflorescence unisexual or bisexual (androgynous), simple or much-branched. ♂ Inflorescence erect. ♀ Flowers in dichasial clusters of 3-15; ovary trigonous in cros-section; staminodes absent. Terminal buds not conferted, scales imbricate. Leaves in whorls of 3; stipules interpetiolar. |
