| 1. | Ferns or related plants, reroducing by spores, not seeds | Group 1 |
| 1. | Plants reproducing by flowers and seeds | Go To 2 |
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| 2. | Plants woody, either trees or shrubs | Group 5 |
| 2. | Plants herbaceous, stems not woody | Go To 3 |
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| 3. | Monocots; leaves usually with parallel veins; petals and sepals, if present, usually in 3's or multiples of 3's | Go To 4 |
| 3. | Dicots; leaves usually with net veins; petals and sepals usually in 2's, 4's or 5's or multiples of 4's or 5's | Go To 6 |
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| 4. | Flowers without sepals and petals; each flower subtended by one or more scales and borne in spikelets | Go To 5 |
| 4. | Flowers with sepals and petals (green or brown or black in Juncus), the flowers not arranged in spikelets | Group 4 |
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| 5. | At least one or more scales at the base of each spikelet not subtending a flower; stems never triangular | Group 2 |
| 5. | All the scales of a spikelet subtending a flower; stems usually triangular | Group 3 |
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| 6. | At least some of the leaves compound; that is, divided into distinct leaflets | Group 6 |
| 6. | None of the leaves compound, although they may be deeply divided | Go To 7 |
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| 7. | Most or all the leaves opposite or whorled | Group 7 |
| 7. | Most or all the leaves alternate and/or basal | Group 8 |
