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| 1 Ovary inferior; fruit indehiscent (pome). |
| ..2 Upper surface of leaves bearing dark glandular trichomes along the midrib (most easily seen with a 10× hand lens); shrubs |
| ..2 Upper surface of leaves lacking dark glandular trichomes along the midrib; shrubs and trees. |
| ....3 Ovary and fruit 10-locular; inflorescence a raceme (rarely a fascicle); pome < 1 cm in diameter |
| ....3 Ovary and fruit 5-locular; inflorescence a cyme, umbel, or fascicle (lacking an elongated central axis); pome 0.7-10 cm in diameter. |
| ......4 Styles distinct; exocarps (carpels within pericarp) bony and seedlike; trees and shrubs, with thorns |
| ......4 Styles usually connate at base; exocarps leather or papery and easily opened to expose seeds; small trees, unarmed, or armed with sharp spur branches. |
| ........5 Pome globose to ovoid, lacking stone cells; anthers yellow to white; styles connate at the base; leaves blunt to acuminate; [apples and crabapples] |
| ........5 Pome globose or pyriform, with stone cells; anthers reddish; styles distinct; leaves acute to acuminate; [pears] |
| 1 Ovary superior; fruit dehiscent (aggregate of follicles, or capsule) or indehiscent (drupe, aggregate of drupelets, aggregate of achenes). |
| ..........6 Leaves opposite; fruit an aggregate of usually 3-5 purple to black drupelets; [tribe Kerrieae] |
| ..........6 Leaves alternate; fruit various (see below; if an aggregate of drupelets, then with >5 drupelets). |
............ 7 Leaves large, > 10 cm wide, palmately veined, palmately lobed; fruit an aggregate of drupelets; [tribe Rubeae] |
| ............ 7 Leaves smaller, < 8 cm wide, pinnately veined, either not lobed or basally pinnately lobed; fruit a drupe, a capsule, an aggregate of follicles, or an aggregate of achenes. |
| ............ ..8 Leaves singly serrate or entire (rarely, as in Prunus americana, irregularly and slightly doubly serrate), not lobed basally. |
| ............ ....9 Gynoecium of separate carpels; fruit an aggregate of follicles; [tribe Spiraeeae] |
| ............ ....9 Gynoecium of fused carpels; fruit either a fleshy drupe or a capsule. |
| ............ ......10 Ovary 5-angled in ×-section; fruit a 5-angled capsule; leaves obovate, obviously broadest towards the tip; [tribe Osmaronieae] |
| ............ ......10 Ovary circular in ×-section; fruit a fleshy spherical drupe; leaves generally broadest near or below the middle; [tribe Amygdaleae] |
| ............ ..8 Leaves doubly serrate, also often lobed towards the base. |
| ............ ........11 Corolla yellow; stems arching, green; fruit an aggregate of drupe-like achenes (dry and indehiscent); [tribe Kerrieae] |
| ............ ........11 Corolla white to pink or rose; stems not both arching and green; fruit various (see below). |
| ............ ..........12 Inflorescence a dense, umbel-like corymb; leaf apices rounded to acute; fruit an aggregate of 5 follicles; [tribe Neillieae] |
| ............ ..........12 Inflorescence a raceme or a leafy panicle; leaf apices acuminate. |
| ............ ............ 13 Fruit a single follicle; [alien, planted, and rarely naturalized, as in e. VA]; [tribe Neillieae] |
| ............ ............ 13 Fruit an aggregate of 2-4 drupe-like achenes; [rare native of calcareous habitats in sc. TN, nw. GA, n. AL, and disjunct westward in AR and MO]; [tribe Kerrieae] |
| 1 Leaves (all) simple; stems unarmed. |
..2 Leaves palmately lobed, orbicular, coarsely toothed, 9-30 cm long; plant a shrub, 10-20 dm tall; petals deep pink; [genus Rubacer or subgenus Anoplobatus – mapleleaf raspberries] |
| ..2 Leaves unlobed, elliptic to ovate-orbiculate, finely toothed, 1.5-3 cm long; plant an herb, < 1 dm tall; petals white; [genus Dalibarda or subgenus Dalibarda] |
| 1 Leaves 3-9-foliolate (reduced simple leaves may also be present in the inflorescence); stems generally armed with prickles (sparsely so in a few species). |
| ....3 Upright stems herbaceous, annual, not differentiated into primocanes and floricanes, unarmed or with a few weak bristles; stipules oblanceolate; [e. WV northward]; [subgenus Cylactis – dwarf raspberries] |
| ....3 Upright stems woody, biennial, differentiated into primocanes and floricanes, these usually well-armed with bristles and/or curved prickles; stipules linear; [collectively widespread]. |
| ......4 Fruit separating from the receptacle, the receptacle remaining on the pedicel; stems either strongly white-glaucous (R. occidentalis), or densely beset with slender-based prickles and bristles (R. idaeus), or densely hairy with 3-5 mm long glandular hairs (R. phoenicolasius), or if not as above then the leaves pinnately 5-9-foliolate (R. illecebrosus) or with a rhombic terminal leaflet about as wide as long and densely white-tomentose below (R. parvifolius); [raspberries]. |
| ......4 Fruit retaining the receptacle; stems or leaves not as described above, except if beset with slender-based prickles and bristles then also < 1 m tall; [blackberries and dewberries]. |
| ........5 Canes very coarse, scrambling, often 2-5 m long, heavily armed; inflorescence cymose-paniculate; branches and pedicels of the floricanes armed with strong, flattened prickles (recurved cat’s-claw, or nearly straight in R. bifrons); [alien, generally in disturbed habitats]; [Eurasian blackberries]. |
| ........5 Canes delicate to coarse, arching or trailing, 0-4 m long, unarmed to strongly armed; inflorescence racemiform; branches and pedicels of the floricanes generally unarmed; [native, though often in disturbed habitats]. |
| ..........6 Primocanes prostrate, creeping, or low-arching, rooting at the tip or also at the nodes; [dewberries]. |
| ..........6 Primocanes erect, ascending, or high-arching, not rooting; [native blackberries]. |
| 1 Lianas. |
| ..2 Lianas climbing by adventitious roots |
| ..2 Lianas climbing by twining or by tendrils. |
| ....3 Lianas climbing by twining |
| ....3 Lianas climbing by tendrils. |
| ......4 Tendrils branched, leaf-opposed; leaves mostly 5-7-lobed, the margins also serrate or dentate |
| ......4 Tendrils simple (though paired in Smilax in SMILACACEAE), axillary; leaves 3-lobed, the margins entire, serrulate, or prickly. |
| ........5 Leaves longer than wide, entire or prickly-margined; stems armed with prickles; flowers 6-merous, greenish, in umbels borne in leaf axils; tendrils stipular, 2 per leaf axil, adnate to the petiole basally |
| ........5 Leaves wider than long, entire or serrulate; stems not armed; flowers 5-merous, blue-purple or yellow, solitary or in small fascicles in leaf axils; tendrils 1 per leaf axil |
| 1 Trees or shrubs. {add: Vernicia in EUPHORBIACEAE, Firmiana in MALVACEAE, Kalopanax in ARALIACEAE, Ficus in MORACEAE} |
| ..........6 Trees. |
| ............ 7 Leaves > 3 dm long and wide; tree monopodial, with a single, unbranched stem (rarely with a few branches). |
| ............ ..8 Leaf lobes > 15, not sublobed; venation of each lobe parallel; fruit a drupe, with 1 seed; [Monocots] |
| ............ ..8 Leaf lobes < 13, most of these sublobed; venation of each lobe pinnate; fruit either a many-seeded berry or a single-seeded nutlet; [Eudicots]. |
| ............ ....9 Petiole attachment marginal; leaf lobes mostly sublobed; fruit a large berry, with many seeds |
| ............ ....9 Petiole attacment peltate; leaf lobes not sublobed; fruit an nutlet, single-seeded |
| ............ 7 Leaves < 3 dm long and wide; tree branching; [Eudicots]. |
| ............ ......10 Leaves 2-lobed (deeply notched at the apex, each lobe separated by the midvein, asymmetrical; [peninsular FL and s. TX] |
| ............ ......10 Leaves 3-5 (-7) lobed; [collectively widspread]. |
| ............ ........11 Leaf blades (3-) 5 (-7) lobed, to 15 cm wide and long, each lobe finely serrate-crenate (>3 teeth per cm of margin) and rarely with a small sub-lobe; multiple fruit spherical and spiky, consisting of multiple bird-beak-like loculicidal capsules; buds axillary |
| ............ ........11 Leaves 3 (-5)-lobed, to 35 cm wide and long, each lobe coarsely toothed or sublobed, the teeth or sublobes (at most 1-2 per cm of margin) attenuate-acuminate; multiple fruit spherical and merely rough on the surface, consisting of multiple achenes with tawny bristles; buds infrapetiolar (completely hidden in the swollen petiole base) |
| ..........6 Shrubs. |
| ............ ..........12 Leaf lobe margins entire (or undulate to sublobed at the tip) |
| ............ ..........12 Leaf lobe margins serrate. |
| ............ ............ 13 Leaves glabrous |
| ............ ............ 13 Leaves pubescent (slightly or strongly). |
| ............ ............ ..14 Pubescence of simple hairs; plants armed or not with nodal spines |
| ............ ............ ....15 Leaves 10-30 cm long and wide; fruit a berry; inflorescence of solitary to a few flowers, or a raceme |
............ ............ ....15 Leaves 2-10 cm long and wide; fruit an aggregate of drupelets; inflorescence a cyme |
| ............ ............ ..14 Pubescence of stellate hairs; plants unarmed. |
| ............ ............ ......16 Leaves > 30 cm wide |
| ............ ............ ......16 Leaves < 15 cm wide |