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1 Leaves oblong or linear-lanceolate, pinnatifid, stipulate; fruit in a bristly involucre formed by 8 bractlets |
1 Leaves mostly obovate or oblanceolate, entire or toothed (especially apically), estipulate; fruit either exposed and densely waxy ( Morella), or partially enclosed in 2 wing-like bractlets ( Myrica). |
..2 Fruit spherical, densely waxy, exposed (the 4-6 bractlets small and inconspicuous); terminal buds present; aments inserted on old wood mainly below the leaves; [collectively common, especially Coastal Plain] |
..2 Fruit flattened, not waxy, partially enclosed in 2 wing-like bractlets; terminal buds lacking; aments inserted at the summit of the branchlets of the preceding year; [rare, either in NC and VA and restricted to Mountain wetlands, or in PA and NJ and northwards] |
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..2 Leaves 1-2 (-4) cm long, 0.11-0.3 (-0.5) mm wide, each with > 40 terete lobes; plant white or silvery-gray; inflorescence an involucrate head |
..2 Leaves longer and/or wider, with a few to many flattened (< 30) lobes; plant green; inflorescence various, but not as above. |
....3 Leaves > 6× as long as wide, the 14-30 lateral lobes evenly arrayed from leaf base to leaf apex; fresh plants strongly aromatic; leaf surfaces dotted with golden-yellow glands, and also pubescent |
....3 Leaves < 4× as long as wide, the 2-12 lateral lobes either evenly arrayed from leaf base to leaf apex, or strongly basally oriented; fresh plants not aromatic; leaf surfaces variously pubescent, but lacking golden-yellow glands. |
......4 Leaf blades 4-30 cm long; leaf lobing evenly from base to apex, or predominantly towards the tip of the leaf; flowers small, in catkins |
......4 Leaf blades 2-7 cm long; leaf lobing predominantly basal (hastate, or with larger basal lobes becoming smaller and more like serrations towards the apex); flowers larger, in various diffuse inflorescences. |
........5 Leaves hastate, with 2 acute basal lobes, merely serrate towards the apex; [exotic species, of s. GA southward] |
........5 Leaves lobate towards base, the lobes rounded in outline, progressively less lobed towards the apex, becoming doubly serrate upwards; [native and exotic species, collectively widespread] |
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..........6 Leaves even-pinnately lobed, with 4 (or sometimes 6 or 8) lobes, the apex a very broad V-notch or truncate |
..........6 Leaves odd-pinnately lobed, with 3, 5, 7, etc. lobes (or sometimes with 2 lobes, but one obviously central and the other smaller and to the side, mitten-like), the apex obtuse to acute. |
............ 7 Leaf lobe margins entire. |
............ ..8 Leaves deeply 2- or 3-lobed (or rarely with 1-4 additional very small, tooth-like lobes towards the base), most branches with a mixture of unlobed, 2-lobed (mitten), and 3-lobed leaves; fruit a blackish-seeded drupe; fresh plants strongly aromatic |
............ ..8 Leaves shallowly or deeply 3-25-lobed; fruit either an acorn or a rather fleshy spherical multiple fruit; fresh plants not aromatic. |
............ ....9 Leaves shallowly or deeply 3-25-lobed; fruit a nut in a cupule (an acorn) |
............ ....9 Leaves shallowly 3-lobed (or mostly unlobed); fruit a rather fleshy multiple fruit |
............ 7 Leaf lobe margins serrate. |
............ ......10 Leaves irregularly toothed, the teeth tipped by a soft bristle; fruit a nut in a cupule (an acorn); small to large trees |
............ ......10 Leaves evenly and rather finely serrate, not bristly-tipped; fruit at least somewhat fleshy, either a pome or a multiple of nutlets surrounded by a fleshy calyx; small trees. |
............ ........11 Petals absent (the individual flowers inconspicuous and aggregated into catkins); fruit a multiple, of nutlets surrounded by a fleshy calyx (mulberry) or a syconium (fig); leaves mainly larger, at least some on a branch > 8 cm long |
............ ........11 Petals 5, conspicuous, white or pink; fruit a pome; leaves mainly small, generally < 8 cm long |