1 Herbs or suffruticose, < 0.9 dm tall

1 Trees and shrubs, nearly always > 10 dm tall.

  2 Leaves compound.

    3 Leaves pinnately compound with > 5 leaflets; petals absent; fruit a samara; small to large tree; [tribe Oleeae, subtribe Fraxininae]

    3 Leaves trifoliolate; petals 6-10, yellow, conspicuous; fruit a deeply 2-lobed dryish berry; [tribe Jasmineae]

  2 Leaves simple.

      4 Flowers bright yellow, showy; fruit a many-seeded capsule; [tribe Forsythieae]

      4 Flowers white, lilac, or purplish; fruit a drupe or 4-seeded capsule.

        5 Leaves cordate or truncate at the base; fruit a 4-seeded capsule; corolla lobes shorter than the tube; flowers lilac or white, in terminal panicles; [tribe Oleeae, subtribe Ligustrinae]

        5 Leaves cuneate to rounded at the base; fruit a drupe; corolla lobes either shorter or longer than the tube; flowers white or greenish-white, in terminal or lateral panicles or fascicles.

          6 Corolla present (often conspicuous and showy); calyx present; flowers in lateral or terminal panicles or in terminal subumbellate clusters.

             7 Corolla lobes 5-12; flowers in terminal subumbellate clusters; [tribe Jasmineae]

             7 Corolla lobes 4; flowers in axillary or terminal panicles or axillary fascicles.

               8 Corolla lobes elongate, much longer than the corolla tube; [tribe Oleeae, subtribe Oleinae]

               8 Corolla lobes short, no longer than the corolla tube.

                 9 Inflorescence a many-flowered terminal panicle; leaves generally ovate, elliptic or lanceolate (widest below or at the middle); [tribe Oleeae, subtribe Ligustrinae]

                 9 Inflorescence a few-flowered axillary panicle or fascicle; leaves generally oblanceolate or obovate (widest above the middle); [tribe Oleeae, subtribe Oleinae].

                   10 Leaf margins entire; leaves usually >7 cm long; inflorescence an axillary panicle (with a central axis); [native tree of Coastal Plain forests]

                   10 Leaf margins on at least some leaves coarsely spinose-serrate; leaves < 10 cm long; inflorescence an axillary fascicle (lacking a central axis); [horticulturally planted, rarely naturalizing]

1 Leaves evergreen.

  2 Plant a shrub, erect, not requiring support.

    3 Leaves with spiny margins; fruit a drupe; [uncommon horticultural escapes].

      4 Flowers 5-merous, the petals clawed; leaves usually small (ca. 2-3 mm long or less); [FL]

      4 Flowers 4-merous; petals not clawed; leaves larger (the longer leaves usually > 3 mm long); [NC northeastward]

    3 Leaves with crenate or serrate margins (the teeth not bearing small spines); fruits various; [widespread natives and non-natives]

        5 Leaves slightly to strongly fleshy; inflorescence a head; [maritime situations]

        5 Leaves not fleshy; inflorescence either a head or otherwise; [collectively widespread].

          6 Leaves > 8 cm long, typically spotted with yellow, coarsely toothed; fruit a red drupe; [commonly cultivated, rarely seeding down nearby]

          6 Leaves < 8 cm long, not yellow-spotted, serrulate; fruit a capsule or purplish drupe; [plants native or cultivated].

             7 Inflorescence a head; [s. FL]

             7 Inflorescence otherwise; [more widespread].

               8 Corolla tubular, campanulate, bilaterally symmetrical; fruit a 1-seeded achene (rarely produced)

               8 Corolla radially symmetrical, with 4-5 distinct petals; fruit a 2-10-seeded capsule or drupe.

                 9 Fruit a 4-5-locular capsule, with 2 seeds per locule (though often fewer by abortion)

                 9 Fruit a (2-) 3-locular, purplish-black drupe, with (2-) 3 single-seeded stones

  2 Plant a subshrub, creeping shrub, or liana.

                   10 Leaves spinose-serrate; [exotics, rarely naturalized]

                   10 Leaves serrate (not spinose), serrulate, or crenate; [exotics and natives, collectively widespread].

                     11 Leaves slightly to strongly fleshy; inflorescence a head; [maritime situations]

                     11 Leaves not fleshy; inflorescence otherwise; [collectively widespread].

                       12 Leaves on vigorous shoots with a few coarse rounded teeth towards the base (most leaves entire)

                       12 Leaves serrulate to serrate, the teeth uniformly around the margin or concentrated towards the tip; fruit dry, either indehiscent and 1-seeded or capsular and with several seeds.

                          13 Flowers 5-merous; petals fused; fruit indehiscent, 1-seeded; [montane, from e. TN, WV, and w. MD northwards in our area]

                          13 Flowers 4- or 5-merous; petals separate; fruit capsular, dehiscent, several-seeded; [collectively widespread in our area]

1 Leaves deciduous.

                            14 Leaves slightly to strongly fleshy; inflorescence a head, subtended by an involucre of phyllaries; [maritime situations]

                            14 Leaves not fleshy; inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head subtended by bracts, but then with other features differing, such as stamens 4, or green calyx present, or petals separate, or fruit a schizocarp of mericarps, etc.); [collectively widespread].

                              15 Lianas climbing by twining or by adventitious roots.

                                16 Stems with retrorse prickles; foliage scabrous

                                16 Stems not prickly; foliage smooth to variously hairy, but not scabrous.

                                  17 Leaves on vigorous shoots with a few coarse rounded teeth towards the base (most leaves entire), the larger leaves < 3 cm wide; lianas climbing by twining; fruit a fleshy berry; flowers 5-merous, with a fused, tubular corolla

                                  17 Leaves serrate, the teeth towards the leaf apex, the larger leaves > 4 cm wide; lianas climbing by adventitious roots; fruit a capsule; flowers 7-10-merous, with separate petals

                              15 Upright shrubs or trees, lacking any adaptations for climbing.

                                    18 Trees; leaves often a mix of alternate and opposite.

                                       19 Leaves harshly scabrous on the upper surface; fruit a multiple of achenes; leaf venation pinnate but irregular

                                       19 Leaves not scabrous; fruit a 2-4-seeded drupe; leaf venation neatly pinnate, the lateral veins nearly straight and parallel to one another

                                    18 Shrubs or trees; leaves strictly opposite (or often subopposite in RHAMNACEAE).

                                         20 Trees; leaves palmately-veined, with 5 or more veins from the base; [rarely naturalizing]

                                         20 Shrubs; leaves either triple-veined from near the base or pinnate-veined; [collectively widespread and common]

                                           21 Leaves strongly triple-veined from at or near the base of the blade, the 2 lateral veins arching towards the tip and rejoining the midvein or nearly so (becoming diffuse before rejoining); petals 4, white; stamens 15-90

                                           21 Leaves pinnate-veined; petals various, not both 4 and white (except sometimes in Hydrangea); stamens 1-15 (except 15-30 in Exochorda in ROSACEAE).

                                             22 Inflorescence head-like; flowers sympetalous and 4-lobed; fruit 2 seeded

                                             22 Inflorescence more diffuse, with internal axes and pedicels; flowers not BOTH sympetalous and 4-lobed (except in Forsythia and Buddleja, which have conspicuous axillary or paniculate inflorescences); fruit 1-seeded, 2-4-seeded, or 4-many-seeded.

                                               23 Plants in flower.

                                                 24 Corolla absent; flowers inconspicuous and small, in axillary fascicles or catkins.

                                                    25 Flowers in catkins; leaves usually a mix of opposite and alternate

                                                 24 Corolla present; flowers larger, in terminal cymes, corymbs, racemes, panicles, or in axillary cymes or fascicles.

                                                      26 Petals separate; stamens 8-10 (-60) (or 4-6 in RHAMNACEAE and Euonymus in CELASTRACEAE).

                                                        27 Flowers 1-few, in axillary cymes; stamens 4-6; stems brown, tan, gray, or green.

                                                          28 Leaf venation pinnate, but irregular and reticulated; stems green

                                                          28 Leaf venation neatly pinnate, the lateral veins nearly straight and parallel to one another; stems brown, tan, or gray

                                                        27 Flowers 1 and terminal, or many, in terminal panicles or corymbs; stamens 8-10 (-60); stems brown, tan or gray.

                                                            29 Inflorescence a solitary, terminal flower; stamens 30-60

                                                            29 Inflorescence a terminal panicle or corymb; stamens 8-15

                                                      26 Petals fused, at least basally, and often strongly tubular; stamens 2, 4, or 5.

                                                              30 Stamens 5.

                                                                 31 Petals white, fused basally only, the lobes spreading

                                                                 31 Petals pink, yellow, or reddish, fused for most of their length

                                                              30 Stamens 2 or 4.

                                                                   32 Stamens 2; petals yellow; flowers radially symmetrical; inflorescence an axillary fascicle

                                                                   32 Stamens 4; petals white, pink, or lavender; flowers bilabiate; inflorescence a terminal thyrse or panicle or an axillary cyme.

                                                                     33 Petals 4; inflorescence a terminal thyrse

                                                                     33 Petals 5; inflorescence a terminal panicle or an axillary cyme.

                                                                       34 Inflorescence an axillary cyme

                                                                       34 Inflorescence a terminal panicle

                                                                         35 Flowers lavender; fruit a shiny orange drupe (appearing berry-like)

                                                                         35 Flowers pinkish-white; fruit a bristly achene

                                               23 Plants in fruit.

                                                                           36 Fruit a berry, drupe, or achene, indehiscent, fleshy at maturity (or dry in Kolkwitzia).

                                                                              37 Fruit a berry, with 20+ seeds

                                                                              37 Fruit a drupe or achene, with 1-4 seeds.

                                                                                38 Fruit an achene (1-seeded), dry at maturity

                                                                                38 Fruit a drupe (1-4-seeded), fleshy at maturity.

                                                                                  39 Inflorescence a terminal corymb

                                                                                  39 Inflorescence axillary, fascicled or a cyme.

                                                                                    40 Foliage with stellate hairs; fruit a pink-purple 4-seeded drupe

                                                                                    40 Foliage glabrous or with simple hairs; fruit a dark red, black, or blue 1-4-seeded drupe.

                                                                                      41 Fruit a 2-4-seeded drupe; [widespread in our region]

                                                                           36 Fruit a capsule, dehiscent, dry at maturity.

                                                                                        42 Inflorescence a catkin, the flowers small (< 5 mm in diameter) and tightly arranged on the inflorescence axis (> 5 per cm of the axis)

                                                                                        42 Inflorescence various, but more diffuse, the flowers larger (> 5 mm in diameter, except for some flowers in Hydrangea in HYDRANGEACEAE) and loosely arranged (< 5 per cm of axis).

                                                                                           43 Capsule prominently 5-angled (star-shaped in ×-section)

                                                                                           43 Capsule not angled.

                                                                                             44 Inflorescence axillary, fascicled.

                                                                                               45 Capsule pink to red; fruits solitary or in axillary cymes

                                                                                               45 Capsule brown; fruits in axillary fascicles

                                                                                             44 Inflorescence terminal, a raceme, panicle, corymb, or compound cyme or thyrse.

                                                                                                 46 Inflorescence a flat-topped corymb or rounded compound cyme, as wide as or wider than long

                                                                                                 46 Inflorescence elongated, a raceme, panicle, or thyrse, much longer than wide.

                                                                                                   47 Capsule elongate (> 3× as long as wide), 8-25 mm long

                                                                                                   47 Capsule about as long as wide, 3-6 mm long.

                                                                                                     48 Sepal lobes 5

                                                                                                     48 Sepal lobes 4