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| 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; [alien trees]. |
| ............ 7 Petioles 9-19 cm long; [subfamily Crotonoideae] |
| ............ 7 Petioles 2-6 cm long; [subfamily Acalyphoideae] |
| ..........6 Leaf blades 1.5-5× as long as wide; native or alien 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; [alien, 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 with copious white latex; [subfamily Euphorbioideae] |
| ............ ............ ............ ............ ..26 Flowers not enclosed in a cyathium; plant 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 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 |