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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; [alien 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 alien 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 |
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..2 Petiole flanged or winged, constricted at the base of the blade; fruit a hesperidium |
..2 Petiole linear (not flanged or winged with leafy tissue); fruit various. {add to 2b: [ Sapium] EUPHORBIACEAE, [ Photinia] ROSACEAE, [ Prunus (caroliniana)] ROSACEAE, [ Ilex (cassine, myrtifolia)] AQUIFOLIACEAE} |
....3 Leaves 7-20 cm long, usually at least some on a branch > 12 cm long, thick in texture but readily flexible when fresh. |
......4 Inflorescence of a solitary flower, axillary, 5-7 cm across; fruit a capsule, ca. 1 cm in diameter |
......4 Incflorescence a corymb of many, smaller flowers; fruit a pome, 0.4-0.8 (-1.2) cm in diameter |
....3 Leaves 3-12 cm long, thick in texture and also noticeably stiff. |
........5 Leaf with a spinose margin, the marginal spines well-developed, generally arrayed along most of the leaf margin and borne at nearly a right angle to the midvein |
........5 Leaf margins serrate with one or a few stiff teeth (sometimes sharpish, but not spines), these usually towards the apex of the leaf and oriented towards the leaf apex |
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..........6 Secondary veins neatly pinnate, the veins on each side of the midrib evenly spaced, parallel to one another, and extending nearly or actually to the leaf margin; fruit either a 1-seeded nut (dry, with or without samaroid wings, bracts, a subtending cupule, or an enclosing and valvate involucre) or a fleshy drupe with 2-4 stones. |
............ 7 Leaves doubly-serrate, the number of teeth greater than the number of the pinnate secondary veins (sometimes obscurely so in Planera in ULMACEAE); fruit a nut or samaroid nut, lacking a cupule or valvate involucre, though sometimes associated with green, leaf-like bracts. |
............ ..8 Flowers unisexual, in catkins, the tree monoecious; leaf base symmetrical |
............ ..8 Flowers bisexual, in axillary fascicles, the tree androgynous; leaf base strongly asymmetrical (oblique) or nearly or quite symmetrical. |
............ 7 Leaves singly serrate or crenate, the teeth the same number as the secondary veins; fruit either a fleshy drupe with 2-4 stones, or a nut with a cupule (acorn) or enclosed by a valvate involucre that splits at maturity. |
............ ....9 Fruit a fleshy drupe with 2-4 stones |
............ ....9 Fruit dry, single-seeded (or with 1-4 nuts in Castanea). |
............ ......10 Fruit > 9 mm long or wide, either a nut with a cupule (acorn) or 1-4 nuts enclosed by a valvate involucre that splits at maturity |
............ ......10 Fruit < 9 mm long and wide, leathery, indehiscent, winged or not |
..........6 Secondary veins not as above, usually arching and/or branching or reticulating well before reaching the leaf margin; fruit various. |
............ ........11 Leaves strongly 3-5-veined from the base; leaf blade cordate or truncate, often oblique. |
............ ..........12 Inflorescence terminal, a compound cyme; peduncles and pedicels becoming swollen, fleshy, and juicy at maturity; [plant rarely naturalized] |
............ ..........12 Inflorescence axillary, a solitary flower, a fascicle or cluster, or a cyme; peduncles and pedicels remaining stalk-like; [collectively widespread and common]. |
............ ............ 13 Flowers unisexual, plants monoecious; pith of mature twigs chambered with hollow sections between soft partitions |
............ ............ 13 Flowers bisexual; plants hermaphroditic; pith of mature twigs continuous without hollow sections between partitions. |
............ ............ ..14 Flowers bisexual; inflorescence an axillary cyme; fresh leaves and stems lacking white latex; fruit simple, a 1-seeded nut; main leaf veins splitting several times towards the leaf margin and leading into the teeth without rejoining and forming a marginal vein; basal veins 5, palmate, all joining together at the summit of the petiole; main lateral leaf veins (above the basal veins) often opposite; winter buds with 3 entire bud scales (1 much smaller than the other 2) |
............ ............ ..14 Flowers unisexual, the pistillate inflorescence a head, the staminate inflorescence a catkin, borne on the same tree (monoecious) or on separate trees (dioecious); fresh leaves and stems with white latex; fruit a multiple of fleshy achenes; main leaf veins splitting towards the margin but then rejoining to form a prominent, looping (scalloped) marginal vein; basal veins 3, palmate, sometimes an additional prominent vein on each side joining the lateral vein above its divergence from the petiole end; main lateral leaf veins (above the basal veins) mainly alternate; winter buds with 5 ciliate-margined bud scales |
............ ........11 Leaves pinnately veined; leaf blade base cordate, subcordate, truncate, rounded, or cuneate base, not oblique. |
............ ............ ....15 Inflorescence a terminal raceme of racemes, with more than 50 flowers; petals connate, urceolate; fruit a 5-valved capsule, < 6 mm in diameter; fresh leaves with a sour taste |
............ ............ ....15 Inflorescence various, either with < 30 flowers or if with > 50 flowers a catkin (with a single axis); corolla with separate petals (or petals absent); fruit various, fleshy or dry, if a 5-valved capsule ( Franklinia in THEACEAE), then 15-20 mm in diameter; fresh leaves without a sour taste. |
............ ............ ......16 Pubescence stellate (look especially in vein axils on the undersurface of the leaf) |
............ ............ ......16 Pubescence simple (or absent). |
............ ............ ........17 Flowers very large and showy, 7-9 cm across; fruit a subglobose capsule 1.5-2 cm in diameter |
............ ............ ........17 Flowers less than 2 cm across; fruit either fleshy and indehiscent, a drupe, samara, or pome, or dry and dehiscent, an ovoid or lanceolate capsule < 0.7 cm in diameter. |
............ ............ ..........18 Flowers unisexual, borne either in axillary catkins; trees dioecious; fruit either dehiscent, a lanceoloid or ovoid capsule (SALICACEAE) or indehiscent, a samara ( Eucommia ulmoides). |
............ ............ ............ 19 Plants bearing latex; fruit a samara, 25-32 mm long, the apex emarginate |
............ ............ ............ 19 Plants not bearing latex; fruit a lanceoloid or ovoid capsule |
............ ............ ..........18 flowers bisexual (unisexual in Ilex in AQUIFOLIACEAE), borne variously in terminal or axillary clusters, cymes, racemes, or umbels, but not at all catkin-like; trees hermaphroditic (dioecious in AQUIFOLIACEAE); fruit indehiscent, a fleshy drupe or pome with 1-many seeds. |
............ ............ ............ ..20 Pith of twigs with transverse diaphragms and also continuous between the diaphragms (make a longitudinal section of twig and use at least 10× magnification; look for translucent diaphragms spaced at < 1 mm apart, with whiter pith tissue between them); fruit distinctly longer than broad, a 1-seeded drupe |
............ ............ ............ ..20 Pith of twigs lacking diaphragms, continuous and homogeneous; fruit either suborbicular to spherical or pear-shaped, either a several- to many-seeded pome, or a berry-like drupe with 4-8 seeds, or a 1-seeded drupe. |
............ ............ ............ ....21 Vascular bundle scars 1 in each leaf scar; fruit a berrylike drupe with 4-8 bony pyrenes; ovary superior, the calyx persistent at the base of the fruit |
............ ............ ............ ....21 Vascular bundle scars (2-) 3 in each leaf scar; fruit a pome or 1-seeded drupe; ovary either inferior and the calyx persistent at the summit of the fruit ( Amelanchier, Crataegus, Malus, Pyrus) or superior and the calyx not at all persistent at the base of the fruit ( Prunus) |