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| 1 Plant woody or suffrutescent, a shrub or a small tree 1-10 m tall; petals present, showy, 8-20 mm long. |
| ..2 Aquatic shrubs with arching suffrutescent or woody stems; leaves opposite or whorled; [native] |
| ..2 Terrestrial shrubs or small trees with erect woody stems; leaves alternate to subopposite; [aliens cultivated and sometimes persistent]. |
| ....3 Flowers in many-flowered terminal or axillary cymose panicles; fruit a loculicidal capsule |
| ....3 Flowers solitary or several in terminal or axillary clusters; fruit a leathery berry (pomegranate) |
| 1 Plant not woody, an herb 0.1-1.2 m tall; petals absent or present, inconspicuous or showy, 1-10 mm long. |
| ......4 Fruit with 2-4 prominent spines; leaves coarsely toothed |
| ......4 Fruit not spinose; leaves entire. |
| ........5 Stems pubescent. |
| ..........6 Floral tube (hypanthium) swollen obliquely at its base; capsule dehiscing longitudinally along the upper surface |
| ..........6 Floral tube (hypanthium) symmetrical; capsule dehiscing septicidally at the apex |
| ........5 Stems glabrous. |
| ............ 7 Floral tube cylindric to turbinate, about 2× as long as wide |
| ............ 7 Floral tube campanulate to globose, about 1× long as wide. |
| ............ ..8 Flowers or fruits (1-) 3-10 in the leaf axils (at least some axils with 2 or more flowers or fruits on a given plant) |
| ............ ..8 Flowers or fruits solitary in the leaf axils (never > 1 per axil). |
| ............ ....9 Capsule indehiscent; petals 0; sepals 4, broadly triangular, lacking intersepalary appendages; seeds spatulate or oblanceolate, about 1 mm long, minutely granular on one face and smooth on the other |
| ............ ....9 Capsule dehiscing septicidally; petals 4; sepals 4 (-6), triangular, with intersepalary appendages of size about equal to the calyx lobes; seeds hemispheric, about 0.3 mm long, the surface very finely reticulate |