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| 1 Leaves deeply pinnately lobed, the lobes linear; plant perennial; mature calyx shallowly toothed, obovoid-urceolate, reticulate-veiny; [section Adenois] |
| 1 Leaves serrate to sinuate-pinnatifid, the lobes broad-based and triangular-tapered; plant annual; mature calyx deeply lobed, neither reticulate nor prominently veined. |
| ..2 Flowers in a slender thyrsoid inflorescence of lateral cymes; [section Botryoides] |
| ..2 Flowers either solitary and spaced along the inflorescence axis, or in dense glomerules arranged secondarily into spikes and panicles. |
| ....3 Flowers solitary, sessile, and spaced along the inflorecence axis; calyx lobes strongly keeled, at maturity with a continuous, horizontal, scarious wing; [section Adenois]. |
| ....3 Flowers in dense glomerules arranged secondarily into spikes and panicles; calyx lobes not winged. |
| ......4 Leaf blades 2-8 cm long; seeds mostly horizontal; stems 3-15 dm tall; [section Adenois]. |
| ........5 Inflorescences foliose throughout; primary leaves not lobed |
........5 Inflorescences leafless (leaves in the inflorescence absent or shorter than the glomerules); primary leaves regularly lobed |
| ......4 Leaf blades 0.5-2.7 cm long; seeds vertical; stems 0.5-5 dm tall; [section Dysphania]. |
| ..........6 Perianth segments rounded |
| ..........6 Perianth segments keeled and/or crested |
| ............ 7 Perianth segments keeled only |
| ............ 7 Perianth segments both keeled and crested |