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| 1 Leaves alternate (the internodes typically short and therefore the leaves looking nearly whorled) |
| 1 Leaves opposite. |
| ..2 Veins usually 5 or more per leaf side. |
| ....3 Bark of older branches and stems splitting longitudinally, appearing braided; leaves without tufts of trichomes in axils of secondary veins on abaxial surface. |
| ......4 Abaxial leaf surface not coronulate, trichomes appressed and rigid, and erect and curling, on the same leaf, leaf base usually rounded or truncate |
| ......4 Abaxial leaf surface coronulate, trichomes all appressed and rigid, leaf base usually cuneate |
| ....3 Bark of older branches and stems smooth, with scattered protruding lenticels; leaves with tufts of trichomes in axils of secondary veins on the abaxial surface. |
| ........5 Area surrounding lenticels suffused with purple; leaves suborbicular or broadly ovate; 7-9 veins per leaf side; tertiary veins usually prominent |
| ........5 Area surrounding lenticels not differentiated; leaves lanceolate, elliptic, or ovate; 5-7 veins per leaf side; tertiary veins not prominent |
| ..2 Veins usually 3-4 per leaf side. |
| ..........6 Trichomes appressed or slightly raised on the lower leaf surface. |
| ............ 7 Multiple stems from a single rootstock (occasionally appearing rhizomatous from decumbent stems); lenticels not protruding, bark swelling between lenticels; fruit blue |
| ............ 7 Rhizomatous, forming large colonies; lenticels protrude slightly, older stems appear verrucose; fruit white |
| ..........6 Trichomes erect on the lower leaf surface. |
| ............ ..8 Drupes purple-black; shrub short-rhizomatous, the stems therefore clustered; [alien] |
| ............ ..8 Drupes blue to whitish-blue or white; shrub rhizomatous, with aerial stems spaces 1-6 dm apart; [native] |
............ ....9 Petioles 3-7 mm long; leaf veins evenly spaced |
| ............ ....9 Petioles 8-25 mm long; leaf veins emanate from the basal half of the leaf |