1 Leaves alternate; monoecious herb or shrub.

  2 Herb, < 2 (-3) dm tall; leaves 1-4 cm long, glabrous; inflorescence a terminal panicle of cyme

  2 Shrub, > 4 dm tall; leaves 5-15 cm long, pubescent; inflorescence a terminal raceme

1 Leaves opposite; dioecious shrubs (except Santalum, which is a monoecious tree).

    3 Aerial (epiphytic) shrubs, parasitic on tree trunks and branches; leaves either coriaceous and brittle when live, or minute and scale-like

    3 Terrestrial shrubs or trees, parasitic via root connections; leaves herbaceous, flexible when live.

      4 Plants trees; petals rose to maroon-colored; leaves primarily descussate, not distichous; [uncommon non-native, se. FL]

      4 Plants rhizomatous shrubs; leaves typically distichously arrayed; petals greenish or greenish-white; [southeast natives occurring north of FL].

        5 Staminate flowers in terminal umbel-like dichasia; pistillate flowers (and fruits) solitary, terminal; clumped shrub to 4 m tall

1 Plants aerial and epiphytic, hemiparasitic shrubs (usually growing out of the branches of trees)

1 Plants terrestrial, autotrophic or hemiparasitic shrubs or subshrubs.

  2 Leaves succulent, nearly as thick as wide; [brackish to saline situations]

  2 Leaves herbaceous or leathery (succulent in Borrichia), much wider than thick; [various habitats].

    3 Creeping or short subshrubs, the stems primarily prostrate (< 2 dm tall), or spreading-ascending to decumbent and < 3 dm tall (MALPIGHIACEAE, in part; Galphimia primarily erect subshrubs to 1 m tall, of TX only in our area).

      4 Petals clawed, the bases noticeably thinned compared to the broader tips; fruit schizocarps, breaking into 2-3 nutlets or 1-seeded cocci; [in part, Aspicarpa and Galphimia]

      4 Petals not clawed, of relatively similar width from base to tip; fruit various, but never schizocarps of 2-3 nutlets or 1-seeded cocci.

        5 Well-developed leaves 4-6 per stem; inflorescence a head subtended by 4 large white bracts

        5 Well-developed leaves many per stem; inflorescence of individual flowers axillary in pairs or clusters or in terminal cymes.

          6 Flowers yellow; leaves with pellucid or dark punctate glands (use at least 10× magnification)

          6 Flowers white, pale pink, or deep pink; leaves lacking sessile, punctate glands.

             7 Leaves linear; flowers pale to deep pink, 5-merous

             7 Leaves orbicular or elliptic; flowers white to pale pink, 4-merous or 5-merous

               8 Leaves elliptic; flowers 5-merous; fruit a brownish capsule

               8 Leaves orbicular; flowers 4-merous; fruit a red berry

    3 Upright or scrambling shrubs, > 3 dm tall.

                 9 Scrambling shrubs, armed with recurved paired spines at the nodes (except Santalum, which can be a scrambling shrub and has red flowers producing drupe-like fruit bearing an apical circular rim).

                   10 Plants armed with recurved paired spines at the nodes; fruit ribbed, the ribs obviously glandular; petioles not 2-ribbed; flowers greenish-white to yellowish in color

                   10 Plants unarmed; fruit not ribbed, instead drupe-like and bearing a circular rim at the apex; petioles 2-ribbed; flowers red

                 9 Upright shrubs, unarmed.

                     11 Inflorescence a terminal head of many flowers.

                       12 Head spherical, lacking an involucre of conspicuous bracts or phyllaries

                       12 Head flattened, either subtended by 4 large white bracts or by an involucre with >5 green phyllaries.

                          13 Head subtended by 4 large white bracts; leaves with prominently parallel-arcing secondary veins; flowers 4-merous

                          13 Head subtended by an involucre of >5 green phyllaries; leaves with venation otherwise; flowers 5-merous

                     11 Inflorescence otherwise (if terminal, the flowers not arranged in heads), either of a solitary flower, or one of a wide variety of inflorescences with flowers attached at different points along branched or unbranched axes (e.g. axillary).

                            14 Inflorescence flat-topped (broader than long), terminal, a compound cyme or corymb.

                              15 Leaves distinctly 3-veined from the base, the 3 veins converging again at the leaf apex; [s. FL only in our area]

                              15 Leaves with prominently pinnate venation; [collectively widespread]

                                16 Leaves conspicuously glandular-punctate and aromatic; fruit a berry; ovary inferior; flowers with abundant stamens and a cup-shaped hypanthium; (partial; Mosiera, Myrcianthes, Syzygium).

                                16 Leaves not glandular-punctate and aromatic (only herbaceous Hypericum sometimes with black or transluscent leaf punctae, thus keyed instead in S1); flowers with 1-5 or 8-10 stamens; fruit not a berry, instead either a capsule (Hypericum), drupe (Cornus; Viburnum), follicle (APOCYNACEAE), or prominently ribbed and stipitate anthocarp (Pisonia).

                                  17 Fruit prominently ribbed (an anthocarp), the ribs with stipitate glands, the fruit thus usually sticky (this persisting on herbarium specimens)

                                  17 Fruit lacking prominent glandular ribs, the fruit not generally sticky.

                                    18 Fresh plants with white, milky juice; pistils 2, united only by the style and stigma; fruit a pair of linear or fusiform follicles, > 5-8× as long as thick, these variously shaped (terete, compressed, or prominently 3-angled)

                                    18 Fresh plants not exuding a white, milky latex (instead clear or not apparent); pistil 1 (or 2-5 in Hypericum); fruit various, but not of paired, linear follicles (see below).

                                       19 Flowers bright yellow; stamens many; leaves < 1.5 cm wide; fruit a capsule; leaves with pellucid or dark punctate glands (use at least 10× magnification)

                                       19 Flowers white or creamy; stamens 4-5; leaves > 1.5 cm wide; fruit a drupe; leaves lacking sessile, punctate glands.

                                         20 Petals 5; foliage with simple hairs

                                         20 Petals 4; foliage with T-shaped hairs

                            14 Inflorescence either terminal, axillary or leaf-opposed, if terminal elongate (not flat-topped) or flowers solitary; if axillary then variously arranged (sometimes also solitary in the axils).

                                           21 Carpels many (> 9), either separate or fused; stamens many; perianth segments either many and undifferentiated into calyx and corolla, maroon, brown, or yellow (in CALYCANTHACEAE), or differentiated into a fleshy and persistent calyx of 5-9 sepals, and a deciduous corolla of 5-9 red (or white) petals (Punica in LYTHRACEAE).

                                             22 Fruit a wrinkled, 3-7 cm long, brown to black, elliptical aggregate of nearly spherical, large achenes; flowers solitary in axils; perianth segments many and undifferentiated into calyx and corolla, maroon, brown, or yellowish; ovary superior; branches unarmed

                                             22 Fruit a leathery, 4-15 cm in diameter, reddish, spherical berry with obpyramidal seeds surrounded by a juicy sarcotesta (pomegranate); perianth differentiated, the sepals fleshy and persistent on the fruit, the petals deciduous, 5-9, bright red to white; ovary inferior; branches typically armed with axillary spines

                                           21 Carpels 1-5 (-6), fused; stamens either 1-5 or 8-10 (except 10+ in MYRTACEAE); perianth segments 4-5 or 8, variously colored; fruit a simple capsule, drupe, or berry (including berry-like fruit); flowers 2-many, in axillary or terminal inflorescences OR sometimes solitary (MYRTACEAE, SANTALACEAE, and THESIACEAE); [Eudicots].

                                               23 Ovary inferior (flowers epigynous); corolla either absent, radially symmetrical, OR bilaterally symmetrical; fruit either a berry or a 1-seeded drupe (a berry or apically dehiscent capsule in MYRTACEAE).

                                                 24 Leaves conspicuously glandular-punctate and aromatic, evergreen and usually coriaceous; fruit a berry or apically-dehiscent capsule; flowers with abundant stamens and a cup-shaped hypanthium.

                                                 24 Leaves not both conspicuously glandular-punctate nor aromatic, membranous and deciduous; fruit a drupe or berry; flowers with 1-5 or 8-10 stamens, with or without a cup-shaped hypanthium.

                                                    25 Flowers unisexual and plants dioecious; corolla absent; pistillate flowers solitary, staminate flowers in pedunculate umbels or cymes, either terminal or axillary; fruit a 1-seeded drupe; leaves acute to acuminate at the apex

                                                      26 Inflorescences terminal

                                                    25 Flowers bisexual and plants hermaphroditic; corolla present; flowers paired, terminal or axillary, or in axillary spikes; fruit a berry; leaves rounded, obtuse, to acute (or acuminate in Lonicera maackii) at the apex

                                               23 Ovary superior (flowers hypogynous); corolla primarily radially symmetrical (zygomorphic in Citharexylum in VERBENACEAE and MALPIGHIACEAE; absent in Forestiera in OLEACEAE); fruit either a 1-4-seeded drupe, or a many-seeded berry (or berry-like fruit), or a capsule.

                                                        27 Leaves with a conspicuous mix of silvery stellate hairs (upper) and rusty colored scales (lower); ovaries bearing rusty colored scales; flowers small, yellowish and inconspicuous; [nw. PA northward]

                                                        27 Leaves glabrous or nearly so, lacking a conspicuous mix of stellate hairs adaxially and rusty scales abaxially; ovaries not bearing rusty colored scales; flowers of various size and color.

                                                          28 Stamens 8-10, of 2 different lengths in each flower; petals separate, 4-5 (-7), pink purple, 10-15 mm long; stems strongly arching, rooting at the tips; [plants of flooded to saturated wetlands]

                                                          28 Stamens either (1-) 2 (-4), or 4-5, or 10, all of the same length; petals fused (separate in RHAMNACEAE and BUXACEAE, but then < 5 mm long and white or cream), white, bright-yellow, lilac, or pink; stems erect (or at least not arching and rooting at the tips); [plants of various habitats].

                                                            29 Petals separate, 4-5, white or cream; stamens 4-5.

                                                              30 Petals clawed (the bases much thinner than the broader tips); fruit a drupe; inflorescence a terminal raceme (Byrsonima) or axillary corymbs or umbels (Malpighia); [in part, Byrsonima and Malpighia; some vining species will grow shrub-like, but those keyed in J3; TX and FL only in our area]

                                                              30 Petals not clawed, the width similar throughout; fruit a drupe or capsule; inflorescence axillary and terminal.

                                                                 31 Fruit a loculicidal capsule, dehiscing into 3 valves; branches square in ×-section; leaves < 2 cm long; [exotic, cultivated and weakly established, of temperate areas]

                                                                 31 Fruit a drupe with 2-4 pyrenes; branches round or nearly so in ×-section; leaves > 2 cm long; [natives, of peninsular FL]

                                                            29 Petals fused (at least basally), 4-5, white, bright yellow, lilac, or pink; stamens either (1-) 2 (-4) or 10; fruit either a capsule or a 1-seeded drupe.

                                                                   32 Inflorescence a drooping axillary raceme (sometimes minutely so), flowers zygomorphic; fruit a drupe

                                                                   32 Inflorescence various, if a raceme then not conspicuously drooping, flowers actinomorphic; fruit a drupe or capsule.

                                                                     33 Perianth 5-merous; corolla pink; stamens 10; fruit a 5-locular capsule

                                                                     33 Perianth 4-merous; corolla white, bright yellow, or lilac; stamens (1-) 2 (-4); fruit either a 1-seeded drupe or a 2-locular capsule