1 Plant a twining vine (herbaceous or woody at base) to 5 m long; stem with stinging hairs; [subfamily Acalyphoideae]

1 Plant not twining; instead a tree, shrub, or herb (or weakly twining in some Tragia, but then less than 1 m long); stem either armed with stinging hairs, or not armed.

  2 Shrub or tree (woody).

    3 Leaves entire.

      4 Hairs of vegetative parts of the plant (especially the leaf undersurface) present and either 2-branched, stellate, or modified into lepidote scales (use 10× or more magnification); [subfamily Crotonoideae].

      4 Hairs of vegetative parts of the plant (especially the leaf undersurface) absent or unbranched (simple) (use 10× or more magnification).

        5 Flowers enclosed in a cyathium; plant with copious white latex; [subfamily Euphorbioideae]

        5 Flowers not enclosed in a cyathium; plant either with or without white latex (the sap clear to whitish or absent).

          6 Leaf blades 1-1.5× as long as wide; [exotic trees].

             7 Petioles 9-19 cm long; [subfamily Crotonoideae]

          6 Leaf blades 1.5-5× as long as wide; native or exotic shrubs or, rarely, small trees.

               8 Sepals absent; latex watery; leaf margins obscurely gland-toothed; [subtropical hardwood hammocks of far southern FL]; [subfamily Euphorbioideae]

               8 Sepals present; latex absent or watery; leaf margins entire; [various habitats and collectively widespread].

                 9 Latex colorless to whitish, watery; capsules ovoid or ellipsoidal; [FL peninsula and s. TX]; [subfamily Crotonoideae]

                 9 Latex absent; capsules subglobose; [collectively widespread in our region].

                   10 Leaves palmately veined at base; inflorescence bracts not subtended by glands; [s. TX and southwards]; [subfamily Acalyphoideae]

                   10 Leaves pinnately veined; inflorescence bracts with 2 subtending glands; [widespread from NC to FL west to AR and e. TX]; [subfamily Euphorbioideae]

    3 Leaves crenate, serrate, and/or palmately lobed.

                     11 Plants hairy with 2-branched hairs (malpighiaceous trichomes); [subfamily Acalyphoideae]

                     11 Plants either glabrous or hairy with simple or stellate trichomes.

                       12 Leaves palmately lobed, margins entire or serrate.

                          13 Petals absent; inflorescence a panicle; leaf lobe margins serrate; [subfamily Acalyphoideae]

                          13 Petals present; inflorescence a cyme or dichasium; leaf lobe margins entire or serrate; [subfamily Crotonoideae].

                            14 Shrub or tree; inflorescence a fascicle or cyme; capsule ellipsoidal

                            14 Tree; inflorescence a dichasium; capsule subglobose

                       12 Leaves unlobed, margins crenate (obscurely crenate in Hippomane and Adelia) or serrate.

                              15 Leaves 8-20× as long as wide (lanceolate to linear); petiole with 0 or 2 glands at summit.

                                16 Petiole with 2 glands at summit; [exotic, on ballast in Pensacola, FL]

                                16 Petiole lacking 2 glands at summit; [native, widespread in our area]

                              15 Leaves 1-3× as long as wide (elliptic, ovate, or obovate); petiole with 0 or 1 gland at summit.

                                  17 Lower leaf surface densely stellate-pubescent; leaf strongly toothed; [TX]; [subfamily Acalyphoideae]

                                  17 Lower leaf surface glabrous; leaf entire, obscurely crenate, or serrulate.

                                    18 Leaf blades obovate, 2-3× as long as wide, with a rounded apex; petiole < 0.2 cm long; fruit a capsule, 1.0-1.3 cm in diameter; [TX]; [subfamily Acalyphoideae]

                                    18 Leaf blades ovate, 1-2× as long as wide, with an acute apex; petiole 1-6 cm long; fruit a drupe, 1.5-2.5 cm in diameter; [FL]; [subfamily Euphorbioideae]

  2 Herb.

                                       19 Leaves palmately deeply divided into 3-many lobes.

                                         20 Plants with a prominent, round woody shallow subterranean caudex to 13.5 cm in diameter; [subfamily Crotonoideae]

                                         20 Plants lacking a prominent subterranean caudex.

                                           21 Leaves peltate; plant glabrous; stamens 100-1000; [subfamily Acalyphoideae]

                                           21 Leaves cordate to truncate or rounded at base; plant glabrous, stellate, or with conspicuous stinging trichomes; stamens 8-15; [subfamily Crotonoideae].

                                             22 Plant with stinging trichomes; stamens connate

                                             22 Plant lacking stinging trichomes; stamens separate.

                                               23 Latex clear; pubescence stellate

                                               23 Latex white; pubescence absent or of non-stellate hairs

                                       19 Leaves generally not lobed, entire or serrate (rarely pinnately lobed in Euphorbia).

                                                 24 Plants hairy with stellate hairs and/or scales; [subfamily Crotonoideae]

                                                 24 Plants glabrous or hairy with simple or 2-branched hairs.

                                                    25 Plants hairy with 2-branched hairs (malpighiaceous trichomes); [subfamily Acalyphoideae]

                                                    25 Plants glabrous or hairy with simple hairs.

                                                      26 Flowers enclosed in a cyathium; plant (fresh) with copious white latex; [subfamily Euphorbioideae]

                                                      26 Flowers not enclosed in a cyathium; plant (fresh) with or without white latex.

                                                        27 Flowers in terminal spikes; stout perennial with several to many stems arising from a subterranean crown; [subfamily Euphorbioideae]

                                                        27 Flowers strictly axillary or both axillary and terminal, in small clusters, racemes, or spikes; finer perennial or annual, not typically with > 1 stem arising from a subterranean crown; [subfamily Acalyphoideae]

                                                          28 Leaves opposite; carpels 2

                                                          28 Leaves alternate; carpels 3 (sometimes fewer by abortion).

                                                            29 Pistillate flowers subtended by a conspicuous leafy bract

                                                            29 Pistillate flowers lacking a leafy bract.

                                                              30 Plant lacking stinging trichomes; styles deeply multifid; [wetland habitats]

                                                              30 Plant with stinging trichomes; styles undivided; [upland habitats]

1 Leaves evergreen. {add to 1a: [Conocarpus] COMBRETACEAE; [Maytenus] CELASTRACEAE}

  2 Leaves tiny, scale-like, broadest at the base and more or less clasping the stem, < 10 mm long and < 1 mm wide

  2 Leaves larger and broader, > 40 mm long and > 8 mm wide.

    3 Fruit a hesperidium; petiole flanged or winged for most of its length, constricted at the base of the blade (except linear in C. medica)

    3 Fruit various (but not a hesperidium); petiole linear (not flanged or winged with leafy tissue).

      4 Leaves pubescent with stellate hairs or peltate scales (sometimes hairs simple), or glandular punctate, appearing as translucent dots (best seen on lower leaf surfaces, with at least 10x magnification).

        5 Leaves (fresh) strongly odorous, glandular-punctate (appearing as translucent dots), with strongly parallel venation; bark on medium-aged to mature trees papery and peeling

        5 Leaves (fresh) not strongly fragrant, with stellate hairs or punctate scales, leaf venation various but not strongly parallel, bark various but not papery

          6 Vestiture of the lower leaf surface of silvery and/or reddish peltate scales; plants hermaphroditic, the flowers bisexual; fruit a fleshy drupe

          6 Vestiture of the lower leaf surface in part of stellate hairs (and also of simple acicular hairs and gland-tipped hairs); plants monoecious, the male flowers in yellow to brownish catkins, the female flowers solitary or in small spikes; fruit a nut in a cupule (an acorn)

      4 Leaves glabrous, or if hairy, with strictly simple hairs.

             7 Flowers solitary, terminal, large (> 5 cm in diameter); pistils many, carpels separate; petals many (typically > 8); leaves mostly > 10 cm long (at least some on a branch longer than 10 cm); fruit an aggregate of follicles, each dehiscing along 1 suture; stipule scar circumferential at each node, encircling the twig

             7 Flowers either in axillary racemes, panicles, umbels, fascicles, or solitary, or in terminal corymbs, umbels, compound cymes, or racemes, small (< 5 cm in diameter); pistil 1, with 1-8 fused carpels; petals 3-8; leaves < 30 cm long; fruit either a drupe, berry, or capsule; stipule scars either absent or linear or triangular, not circumferentially encircling the twig.

               8 Inflorescence terminal, a corymb, umbel, compound cyme, or raceme; fruit either a capsule (dehiscing along 5 longitudinal sutures) or a few-seeded berry.

                 9 Inflorescence a compound cyme; petals deep red to magenta; fruit a few-seeded drupe

                 9 Inflorescence a corymb, umbel, or raceme; petals white or pink; fruit a capsule, opening by 5 longitudinal sutures.

                   10 Capsules ovoid to globose or subglobose, about as long as broad, 5-8 mm long; leaves 5-12 cm long, 2-3× as long as wide

                   10 Capsules elongate, > 2× as long as broad, 8-18 mm long; leaves 10-30 cm long, 3-5× as long as wide

               8 Inflorescence axillary, a raceme, panicle, umbel, fascicle, or solitary; fruit drupaceous, fleshy to dry, but not regularly dehiscent along sutures.

                     11 Flowers solitary, axillary or superaxillary; perianth somewhat fleshy, in whorls of 3; carpels numerous, partly fused; fruit an aggregate syncarp

                     11 Flowers in inflorescences of > 2 flowers; perianth not fleshy, in whorls of 4 or 5 (or 3 in Lauraceae); carpels 2, 3, 4, or 5, fused; fruit a capsule, drupe, or berry

                       12 Inflorescence an axillary raceme (with an elongate central axis, to which all flowers/fruits are attached).

                          13 Fruit a dry, tan to brown, spherical or winged drupe; stamens 5 or 10; carpels 2-5; leaves oblanceolate (rarely narrowly elliptic), < 2.5 cm wide, the apex obtuse (more rarely acute, retuse, or rounded)

                          13 Fruit a fleshy, black, spherical drupe; stamens 10; carpels 1; leaves elliptic, the apex acute to short-acuminate

                       12 Inflorescence either an axillary umbel or fascicle (or reduced to solitary) or an axillary compound inflorescence (panicle or compound cyme), with 2-3 orders of branching.

                            14 Fruit a fleshy and oily 1-seeded drupe; flowers 3-merous, with separate and undifferentiated perianth segments; fresh plants strongly aromatic; inflorescence compound, a panicle or compound cyme (with 2-3 orders of branching); [Basal Angiosperms]

                            14 Fruit a fleshy but not oily 1-8-seeded drupe or berry; flowers 4-8-merous, with differentiated sepals and petals, the petals usually basally fused; fresh plants not strongly aromatic; inflorescence an axillary umbel or fascicle (or reduced to solitary), a central axis absent or < 1 cm long; [Eudicots].

                              15 Plants unarmed (or with marginal leaf prickles or spines); stamens 4-7, not epipetalous; fruit a drupe with 4-8 pyrenes;flowers 4-7-merous

                              15 Plants armed with nodal thorns; stamens 5 and staminodia 5, epipetalous; fruit a berry or drupe with 1 seed;flowers 5-merous

1 Leaves deciduous.

                                16 Leaf base deeply to shallowly cordate, with 3-7 palmate veins from the base; leaf blade about as wide as long or a little longer, mostly 0.9-1.3× as long as wide.

                                  17 Juncture of petiole and leaf blade with 2 red glands; corolla radially symmetrical, with 5-8 petals, white with red veins towards the base of the petals; flowers unisexual; fruit globose, 4-8 cm in diameter; main palmate leaf veins 3 (-5)

                                  17 Juncture of petiole and leaf blade eglandular, but the uppermost 1-3 mm of the petiole swollen into a prominent upper pulvinus; corolla bilaterally symmetrical, with 5 petals, pink to purple (rarely white in some cultivars); flowers bisexual; fruit an oblong, flat legume, 6-10 cm long; main palmate leaf veins 5-7 (-9)

                                16 Leaf base cuneate, rounded, truncate, subcordate, or auriculate (with 2 small “earlobe-like” lobes at the base of the leaf blade), with 1 (mid) vein from the base (3 veins from the base in Celtis in CANNABACEAE); leaf blade about as wide as long, or somewhat to much longer, 0.9-10× as long as wide.

                                    18 Leaves 0.9-1.4× as long as wide (some taxa keyed in both leads).

                                       19 Stipule scars circumferential, forming a line around the twig; flowers and aggregate fruits solitary, terminal; [Basal Angiosperms]

                                       19 Stipule scars not circumferential (or not apparent); flowers and simple fruits in inflorescences of 1-many flowers, axillary or terminal, but not simultaneously solitary and terminal; [Eudicots].

                                         20 Leaf blade 4-30 cm long, > 3× as long as the stiff petiole.

                                           21 Petioles 1-5 (or more) cm long; leaves broadly orbicular, rounded at the base, usually rounded (rarely obtuse or nearly acute) at the apex, entire; hairs on foliage simple or absent; fruit a fleshy drupe

                                           21 Petioles < 1 cm long; leaves various in shape, often acuminate at the apex and/or cuneate at the base, often with some tendency to toothing; hairs on foliage stellate (use at least 10× magnification), at least in part; fruit either a nut borne in a cup (acorn) or a dry, subglobose 3-valved capsule, with 1 seed.

                                             22 Fruit a nut in a cupule (an acorn); flowers unisexual, greenish or brownish, individually inconspicuous, the male flowers borne in catkins

                                             22 Fruit a dry, subglobose 3-valved capsule, with 1 seed; flowers bisexual, white, conspicuous

                                    18 Leaves > 1.4× as long as wide.

                                               23 Leaves densely covered with silvery peltate scales (use 10× or greater magnification), giving the leaf blade surface a metallic appearance

                                               23 Leaves glabrous, glabrescent or variously pubescent (including densely and silkily so, giving the leaf surface a shiny appearance), but not as above.

                                                 24 Plants bearing nodal thorns; leaves elliptic to obovate, 3-9 cm long, 1-4 cm wide, 1.5-4× as long as wide.

                                                    25 Sap clear, not viscous; sepals 4; petals 4, densely long-hairy on their upper (inner) side); fruit a yellow, 1-seeded drupe, 20-30 mm long; [FL southward]

                                                    25 Sap milky or nearly clear but thick and sticky; sepals 5; petals 5, not densely long-hairy; fruit a black, 5-seeded berry, 5-15 mm long; [widespread in our area]

                                                 24 Plants unarmed (except spiny in Maclura in MORACEAE); leaves various in shape, from broadest towards the base, near the middle, or towards the apex, 3-80 cm long, 1-30 cm wide, 1.5-10× as long as wide.

                                                      26 Leaves distinctly widest near the base (at a point < 0.3× of the way from the base of the leaf blade to its apex), gradually long-tapering to an acuminate apex.

                                                        27 Fruit a spherical, dry drupe, 4-8 mm in diameter, with a single seed; leaf 1.5-6 cm wide

                                                        27 Fruit a spherical, fleshy multiple, 80-120 mm in diameter; leaf 5-8 cm wide

                                                      26 Leaves widest near the middle or towards the tip of the leaf blade (at a point > 0.4× of the way from the base of the leaf blade to its apex).

                                                          28 Pubescence of the foliage stellate (at least in part; simple hairs sometimes present as well); flowers unisexual, the individual flowers inconspicuous, male flowers in catkins; fruit a nut in a cupule (an acorn)

                                                          28 Pubescence of the foliage simple or absent (except stellate in STYRACACEAE); flowers bisexual, conspicuous, borne variously, but not in catkins (except in Leitneria); fruit various.

                                                            29 Leaf undersurface strongly whitened

                                                            29 Leaf surface green (often somewhat paler green than the upper surface, but not whitened).

                                                              30 Flowers unisexual and borne in male and female catkins; plants dioecious

                                                              30 Flowers bisexual, not borne in catkins; plants hermaphroditic.

                                                                 31 Flowers solitary; ovary superior; perianth either 3-merous and whorled or many-merous and spiraled; leaves mostly > 20 cm long and > 8 cm wide, distinctly broadest towards the apex (> 0.6× of the way from the leaf blade base to apex) (except Magnolia acuminata, which is sometimes both shorter, narrower, and broadest near the middle or towards the base); [Basal Angiosperms].

                                                                   32 Flowers axillary, < 2 cm across, brown or maroon; perianth 3-merous, whorled; fresh foliage with a strong musky odor; fruit a fleshy berry; leaves cuneate at the base; twigs lacking circumferential stipule scars at each node

                                                                   32 Flowers terminal, > 4 cm across, white, pale yellow, or pink; perianth many-merous, spiraled; fresh foliage not noticeably aromatic; fruit an aggregate of follicles; leaves cuneate or auriculate at the base; twigs with circumferential stipule scars at each node

                                                                 31 Flowers in inflorescences of several to many; ovary inferior (or superior in Diospyros in EBENACEAE and Cyrilla in CYRILLACEAE); perianth 4-5-merous; leaves mostly < 20 cm long and < 10 cm wide, broadest near the middle or towards the apex; [Eudicots].

                                                                     33 Leaves with prominently parallel-arcing secondary veins; inflorescence a terminal corymb; leaves clustered at the tips of the twigs, thus appearing pseudo-whorled; trichomes of the leaf undersurface predominantly 2-branched (some simple) (use at least 10× magnification); flowers 4-merous; fruit a blue drupe; small tree

                                                                     33 Leaves with secondary veins more obscure and complexly branching into tertiary veins; inflorescence axillary (often on the previous year’s wood), solitary to variously fascicled, clustered, or in racemes; leaves arrayed distichously along horizontal or arching twigs, not prominently clustered or pseudo-whorled (except often in Cyrilla in CYRILLACEAE, Symplocos in SYMPLOCACEAE, and Nyssa in NYSSACEAE); trichomes of the leaf undersurface either simple or stellate (or absent); flowers 4-5-merous; fruit a green, blue, or black drupe, an orange berry, or a green to brownish indehiscent capsule; small to large tree.

                                                                       34 Pubescence of foliage and other parts stellate (use at least 10× magnification); petals 4-5, white, 10-25 mm long; fruit dryish, indehiscent, either longitudinally 2-4-winged or not winged

                                                                       34 Pubescence of foliage and other parts simple; petals either 0, or 4-5 and pink, white, or greenish-yellow, or 10 and greenish-yellow; fruit either a somewhat to very fleshy drupe or berry or a dry, brownish, spherical drupe, 2-2.5 mm in diameter.

                                                                         35 Leaves < 2.5 cm wide, dark green above, somewhat thickened, and tardily deciduous or semi-evergreen; fruit a dry, brownish, spherical drupe, 2-2.5 mm in diameter; inflorescence a narrowly cylindrical raceme with > 40 flowers

                                                                         35 Leaves > 2.5 cm wide, usually medium-green above, herbaceous in texture, promptly seasonally deciduous; fruit a somewhat to very fleshy drupe or berry, > 5 mm in diameter; inflorescence a solitary flower or cluster, head, or irregular raceme of < 15 flowers.

                                                                           36 Fruit a drupe (green when ripe), cylindrical to barrel-shaped, 8-12 mm long; leaves rather thick and leathery in texture, persistent into the winter, dropping tardily or at latest the following spring; flowers bisexual; stamens 30-50, in 5 fascicles

                                                                           36 Fruit a berry (orange when ripe) or a drupe (blue-black, yellow, orange, or red when ripe), 8-50 mm long, spherical or ovoid to ellipsoid; leaves thin in texture, promptly deciduous in the autumn; flowers functionally unisexual; stamens 5-16, separate.

                                                                              37 Fruit a spherical berry, 15-50 mm long, orange when ripe, subtended by the enlarged and persistent woody or leathery calyx; vascular bundles 1 per leaf scar; leaves never toothed; leaves whitish-green beneath; leaf midrib and upper petiole with tiny glands on their upper surfaces (reddish initially, then darkening) (use at least 10× magnification); leaves glabrate to tomentose with curly hairs beneath; female and male flowers on separate trees (dioecious); stamens 16; widest point of the leaf usually at the middle or below, the apex acute to acuminate

                                                                              37 Fruit an ovoid or ellipsoid drupe, 8-30 -40 mm long, blue-black, yellow, orange, or red when ripe; vascular bundles 3 per leaf scar; leaves sometimes bearing a few irregular teeth; leaves pale to medium green beneath; leaf midrib and upper petiole lacking reddish to dark glands on their upper surfaces; leaves glabrous or glabrate beneath; female and male flowers on the same tree (monoecious); stamens 5-12; widest point of the leaf usually beyond or at the middle, the apex obtuse to strikingly and abruptly acuminate