1 Plant a floating aquatic (or stranded), the individual thalloid leaves < 2 cm long; [subfamily Lemnoideae].

..2 Fronds rootless; fronds without nerves; reproductive pouch 1, terminal.

....3 Fronds thick, globoid, < 2 mm long

....3 Fronds flat, elongate and curved, 4-14 mm long

..2 Fronds with roots; fronds with 1 or more nerves; reproductive pouches 2, lateral.

......4 Roots 1 per frond; fronds with 1-5 (-7) nerves

......4 Roots (1-) 2-21 per frond; fronds with (3-) 5-21 nerves.

........5 Roots (1-) 2-7 (-12) per frond; fronds with (3-) 5-7 nerves; fronds 1.5-3× as long as wide; all of the roots perforating the scalelike leaflet

........5 Roots 7-21 per frond; fronds with 7-16 (-21) nerves; fronds 1-1.5× as long as wide; only some of the roots perforating the scalelike leaflet (borne on the underside)

1 Plant terrestrial, rooted in wetlands, or a floating aquatic (if a floating aquatic – Pistia – the individual leaves > 2 cm long).

..........6 Plant a floating aquatic, with gray-green, velvety, cabbage-like leaves; [subfamily Aroideae, tribe Pistieae]

..........6 Plant rooted (even when growing in water), the leaves various, but not as above.

............ 7 Leaves compound (or sometimes very deeply 3-lobed, with only <3 mm leaf tissue connecting the lobes).

............ ..8 Plant an herb, with 1-5 basal leaves; sap clear; [subfamily Aroideae, tribe Arisaemateae].

............ ....9 Spadix free of the spathe; spathe unisexual (with either female flowers only or male flowers only) or bisexual (and then the female and male flowers not separated by a sterile gap); leaves either palmately compound with 3-5 leaflets or pedately compound with 5-15 leaflets, the central leaflet as large as or smaller than the adjacent leaflets; bulblets lacking on the petiole; [native, common].

............ ....9 Spadix fused basally along one side (for several cm) to the spathe; spathe bisexual, with a basal section of female flowers, a sterile gap, a section of male and female flowers on the free side; leaves either palmately compound with 3 leaflets (juvenile leaves sometimes simple or very deeply 3-lobed) or pedately compound with 5-7 (-9) leaflets, the central leaflet as large as or larger than the others; bulblets either absent or present at base and summit of the petiole; [exotic, rarely naturalized]

............ 7 Leaves simple.

............ ......10 Leaves both peltate and cordate-hastate; [subfamily Aroideae, tribe Colocasieae]

............ ........11 Primary lateral veins and midrib of abaxial leaf surfaces with wax glands; mature fruit orange or red and odorless, some containing a few large seeds

............ ........11 Primary lateral veins and midrib of abaxial leaf surfaces without wax glands; fruits inconspicuously colored and odorous, with many small mucilaginous seeds

............ ......10 Leaves not peltate, either cuneate, rounded, cordate, or hastate.

............ ..........12 Spathe absent or obscure; leaf blade 2.5-5× as long as wide, cuneate at the base, lanceolate or narrowly elliptic; leaf venation parallel; [subfamily Orontioideae, tribe Orontieae]

............ ..........12 Spathe present, surrounding the spadix, at least at its base; leaf blade 1-2.5× as long as wide, either hastate at the base (Arum, Peltandra, Syngonium, and Xanthosoma), or rounded (Symplocarpus), or cordate (Calla), broadly ovate in outline.

............ ............ 13 Sap clear; [collectively widespread].

............ ............ ..14 Spathe white; leaves cordate; plants from elongate rhizomes; [MD northward]; [subfamily Calloideae]

............ ............ ..14 Spathe green or white; leaves hastate or rounded at base; plants from fibrous roots, a short thick rhizome, tuber, or a corm; [collectively widespread].

............ ............ ....15 Leaves ovate, rounded or subcordate at the base; spathe purple, or purple flecked with white; [subfamily Orontioideae, tribe Symplocarpeae]

............ ............ ....15 Leaves hastate at the base (somewhat arrowhead-shaped); spathe green or white; [subfamily Aroideae].

............ ............ ......16 Larger leaf blades > 5 dm long; longer petioles 10-20 dm long; [subfamily Aroideae, tribe Caladieae]

............ ............ ......16 Larger leaf blades < 5 dm long; longer petioles < 7 dm long.

............ ............ ........17 Plant from a horizontal tuber; leaves variegated; [exotic, of moist soils]; [subfamily Aroideae, tribe Areae]

............ ............ ........17 Plant from fibrous roots; leaves not variegated; [native, of wetlands]; [subfamily Aroideae, tribe Peltandreae]

1 Leaves 2-foliolate or 1-foliolate (and then deeply notched).

..2 Leaves 1-foliolate (2-lobed)

..2 Leaves 2-foliolate

1 Leaves 3-, 5-, to many-foliolate.

....3 Leaves 3-foliolate.

......4 Plant a liana, climbing by twining, by tendrils, or by adventitious roots.

........5 Leaves untoothed and unlobed

........5 Leaves coarsely toothed or lobed. {add Eleutherococcus trifoliatus ARALIACEAE}

..........6 Leaflets obovate or broadly elliptic (broadest at or above the middle), the teeth or lobes primarily or solely in the apical half of the leaf; plant climbing by leaf-opposed tendrils

..........6 Leaflets orbicular or ovate (broadest at the middle or below the middle), the teeth or lobes primarily or solely in the basal half of the leaf; plant climbing by stem twining or by dense, reddish adventitious roots.

............ 7 Plant climbing by the stem twining; [plant not actually woody, but so robust as to often be assumed to be so]

............ 7 Plant climbing by dense, reddish adventitious roots attaching the stem to tree trunks or rock outcrops

......4 Plant a shrub (sometimes scrambling or occasionally high-climbing with the support of other vegetation, but lacking the specialized climbing structures listed above).

............ ..8 Stems armed with small prickles or stout thorns.

............ ....9 Stems with stout thorns at the nodes; fruit a hesperidium (orange-like, but densely hairy)

............ ....9 Stems with many small prickles along the internodes; fruit either a legume, or an aggregate of drupelets, or a hip.

............ ......10 Leaflets with 2 rounded lateral lobes near the base, otherwise entire; fruit a legume

............ ......10 Leaflets serrate and sometimes also cleft; fruit either an aggregate of drupelets or a hip

............ ..8 Stems unarmed.

............ ........11 Leaflets serrulate, crenulate, serrate, with a few coarse and jagged teeth (spine-tipped or not), or shallowly lobed.

............ ..........12 Leaflets serrulate or crenulate

............ ..........12 Leaflets serrate, with a few coarse and jagged teeth (spine-tipped or not), or shallowly lobed.

............ ............ 13 Leaflets with 2 prominent, rounded lobes near the base; fruit a legume; flowers > 3 cm long, corollas bilaterally symmetrical, red, in a terminal raceme

............ ............ 13 Leaflets serrate and sometimes also cleft, or with a few coarse and jagged teeth (spine-tipped or not); fruit either a tan or red drupe or a red berry; flowers < 1 cm across, corollas radially symmetrical, green, yellow, or white, in axillary or terminal panicles or racemes

............ ............ ..14 Leaflets with a few spine-tipped teeth; fruit a red berry; [TX westwards]

............ ............ ..14 Leaflets not spine-tipped; fruit a red or tan drupe; [collectively widespread]

............ ........11 Leaflets entire and unlobed.

............ ............ ....15 Terminal leaflet sessile.

............ ............ ......16 Leaflets < 2 cm long; stems and branches dark green

............ ............ ......16 Leaflets 5-15 cm long; stems and branches tan to brown

............ ............ ....15 Terminal leaflet with a petiolule.

............ ............ ........17 Leaves pinnately trifoliolate, a rachis present as an extension of the petiole past the point of attachment of the 2 lateral leaflets, the terminal leaflet borne on a petiolule at the terminus of the rachis, with an obvious joint present between the rachis and petiolule

............ ............ ........17 Leaves palmately trifoliolate, the terminal leaflet typically with a longer petiolule than the lateral leaflets, but lacking a rachis (the petiolule of the terminal leaflet attached at the same point as the 2 lateral leaflets and unjointed)

....3 Leaves with 5-many leaflets (poorly developed leaves in some species with only 3 leaflets).

............ ............ ..........18 Leaves palmately or palmately-pedately compound.

............ ............ ............ 19 Leaves palmately-pedately 5-foliolate (the lateral 2 leaflets on each side borne on a common Y-shaped stalk).

............ ............ ............ ..20 Leaflets toothed; sap clear

............ ............ ............ 19 Leaves palmately compound (all the leaflets attached at a single point).

............ ............ ............ ....21 Leaves > 6 dm wide

............ ............ ............ ....21 Leaves < 3 dm wide.

............ ............ ............ ......22 Leaflets with entire margins

............ ............ ............ ......22 Leaflets with serrate margins.

............ ............ ............ ........23 Stems armed with prickles scattered in the internodes

............ ............ ............ ........23 Stems unarmed or with paired nodal spines.

............ ............ ............ ..........24 Inflorescence an umbel; leaves evergreen, glossy; stems often with paired nodal spines

............ ............ ............ ..........24 Inflorescence a panicle; leaves deciduous, dull; stems unarmed

............ ............ ..........18 Leaves pinnately, bipinnately, or complexly compound.

............ ............ ............ ............ 25 Leaves at least in part pinnate-pinnatifid, 2-pinnate, or otherwise more complexly compound than 1-pinnate.

............ ............ ............ ............ ..26 Leaves evenly 2-pinnately compound

............ ............ ............ ............ ..26 Leaves oddly pinnate-pinnatifid, 2-pinnately compound, or more complexly compound than 2-pinnate.

............ ............ ............ ............ ....27 Leaves pinnate-pinnatifid, with 7-19 leaflets, each leaflet pinnatifid into narrowly lanceolate lobes; {upper leaflet surface dark green, lower surface silvery with gray sericeous pubescence}

............ ............ ............ ............ ....27 Leaves 2-pinnately compound, or even more complexly compound.

............ ............ ............ ............ ......28 Plant a liana, climbing by tendrils

............ ............ ............ ............ ......28 Plant a shrub or tree, not climbing.

............ ............ ............ ............ ........29 Plant armed with prickles on the stem, and sometimes also on the axes and main veins of the leaves

............ ............ ............ ............ ........29 Plant unarmed.

............ ............ ............ ............ ..........30 Plant a shrub, < 2.5 m tall.

............ ............ ............ ............ ............ 31 Foliage green; leaflets ovate, acute at the tip; flowers 3-merous, the tepals white or cream; fruit a red berry

............ ............ ............ ............ ............ 31 Foliage blue-green; leaflets obovate, rounded or notched at the tip; flowers 4-5-merous, the sepals green, the petals yellow; fruit a capsule

............ ............ ............ ............ ..........30 Plant a tree, > 3 m tall when flowering and fruiting.

............ ............ ............ ............ ............ ..32 Leaflets entire

............ ............ ............ ............ ............ ..32 Leaflets serrate.

............ ............ ............ ............ ............ ....33 Fruit a globose drupe, tan at maturity, 10-15 mm in diameter; inflorescence an axillary panicle; corolla lavender

............ ............ ............ ............ ............ ....33 Fruit an inflated capsule, 30-50 mm long; inflorescence a terminal thyrse; corolla yellow

............ ............ ............ ............ 25 Leaves 1-pinnately compound.

............ ............ ............ ............ ............ ......34 Leaves even-pinnately compound (generally with 2 leaflets at the apex of the rachis, these obviously and symmetrically paired).

............ ............ ............ ............ ............ ........35 Leaflets rounded to obtuse at the apex (or acute to acuminate in Gymnocladus); fruit a legume; inflorescence various, but not as below

............ ............ ............ ............ ............ ........35 Leaflets acuminate at the apex; fruit a drupe or capsule; inflorescence a panicle with many, small, radially symmetrical flowers.

............ ............ ............ ............ ............ ..........36 Fruit a capsule.

............ ............ ............ ............ ............ ..........36 Fruit a drupe.

............ ............ ............ ............ ............ ............ 37 Tree dioecious; drupe ca. 5 mm long; stamens (of male flowers) 3-5 (-7)

............ ............ ............ ............ ............ ............ 37 Tree bisexual; drupe ca. 13 mm long; stamens 8-10

............ ............ ............ ............ ............ ......34 Leaves odd-pinnately compound (generally with a single leaflet at the terminus of the rachis).

............ ............ ............ ............ ............ ............ ..38 Leaves very large, > 10 dm long

............ ............ ............ ............ ............ ............ ..38 Leaves small to large, < 10 dm long.

............ ............ ............ ............ ............ ............ ....39 Stems armed with prickles or stipular or nodal spines; leaves often also with prickles.

............ ............ ............ ............ ............ ............ ......40 Leaves with conspicuous leafy stipules, often adnate to the petiole; plant a liana or small to medium shrub; leaves serrate, often sharply and prominently so; leaves not strongly aromatic when fresh, lacking pellucid punctate glands on the surface

............ ............ ............ ............ ............ ............ ......40 Leaves lacking leafy stipules; plant a tree or tall shrub; leaves entire or obscurely crenate or serrate; plant a tree or tall shrub; leaves either strongly aromatic when fresh, with conspicuous pellucid punctate glands or not aromatic and not pellucid-punctate.

............ ............ ............ ............ ............ ............ ........41 Leaves not aromatic when fresh, lacking pellucid punctate glands; leaves never with prickles on the rachis; leaflet apices rounded

............ ............ ............ ............ ............ ............ ........41 Leaves strongly aromatic when fresh, with conspicuous pellucid punctate glands; leaves often with prickles on the rachis; leaflet apices usually acuminate

............ ............ ............ ............ ............ ............ ....39 Stems unarmed (leaflets with spinose margins in some species, or the stem with dense hispid hairs).

............ ............ ............ ............ ............ ............ ..........42 Leaflets entire.

............ ............ ............ ............ ............ ............ ............ 43 Plant a liana, climbing by twining

............ ............ ............ ............ ............ ............ ............ 43 Plant an upright shrub or tree, not climbing.

............ ............ ............ ............ ............ ............ ............ ..44 Plant a medium or tall tree.

............ ............ ............ ............ ............ ............ ............ ....45 Leaves with stipules; flowers bilaterally symmetrical, papilionaceous, white, cream, or pink; stamens 10; fruit a legume; [collectively widespread in our area]

............ ............ ............ ............ ............ ............ ............ ....45 Leaves without stipules; flowers radially symmetrical, whitish; stamens 5 or 10; fruit a single-seeded drupe; [FL peninsula]

............ ............ ............ ............ ............ ............ ............ ..44 Plant a shrub or small tree to 7 (-10) m tall.

............ ............ ............ ............ ............ ............ ............ ......46 Leaf 2-5 cm long, with 5-7 leaflets

............ ............ ............ ............ ............ ............ ............ ......46 Leaf > 8 cm long, with 5-many leaflets.

............ ............ ............ ............ ............ ............ ............ ........47 Flowers bilaterally symmetrical, papilionaceous (reduced in Amorpha to a single petal); stamens 10; fruit a legume; leaves with stipules.

............ ............ ............ ............ ............ ............ ............ ........47 Flowers radially symmetrical, stamens 4-5; fruit either a drupe (Anacardiaceae), or a 1-3-seeded berry or a samara (Picramniaceae); leaves without stipules.

............ ............ ............ ............ ............ ............ ............ ..........48 Inflorescence a panicle; fruit a drupe; [collectively widespread]

............ ............ ............ ............ ............ ............ ............ ..........48 Inflorescence a raceme or compound thyrse; fruit a samara or 1-3-seeded berry; [s. FL]

............ ............ ............ ............ ............ ............ ..........42 Leaflets serrate or crenate.

............ ............ ............ ............ ............ ............ ............ ............ 49 Leaflets crenate, the teeth rounded and often inconspicuous.

............ ............ ............ ............ ............ ............ ............ ............ ..50 Leaflets with obscure crenations, not as below nor bearing glands; leaf rachis narrowly to conspicuously winged, especially towards the tip; fruit a drupe; plant a shrub or small tree

............ ............ ............ ............ ............ ............ ............ ............ ..50 Leaflets (especially the basal and on the basalscopic side) with 1-5 large rounded teeth, each bearing a prominent dark green gland; leaf rachis not winged; fruit a schizocarp, with 2-5 samaroid mericarps; plant a medium to large tree

............ ............ ............ ............ ............ ............ ............ ............ 49 Leaflets serrate.

............ ............ ............ ............ ............ ............ ............ ............ ....51 Leaf serrations spinose

............ ............ ............ ............ ............ ............ ............ ............ ....51 Leaf serrations not spinose.

............ ............ ............ ............ ............ ............ ............ ............ ......52 Inflorescences axillary.

............ ............ ............ ............ ............ ............ ............ ............ ........53 Plant a tree, freely branched; rhizome inner bark not brightly colored; flowers unisexual, the male flowers in catkins, the female flowers solitary or few in a spike, the perianth greenish or tan and inconspicuous; fruit a nut covered by a dehiscent or indehiscent involucre

............ ............ ............ ............ ............ ............ ............ ............ ........53 Plant a short shrub, < 1 m tall, little branched; rhizome inner bark of fresh plants bright yellow; flowers bisexual, petals absent, the 5 petaloid sepals maroon; inflorescence a drooping panicle from the base of the new year’s growth; fruit an aggregate of follicles

............ ............ ............ ............ ............ ............ ............ ............ ......52 Inflorescences terminal.

............ ............ ............ ............ ............ ............ ............ ............ ..........54 Inflorescence corymbose (flat-topped or rounded, as wide as long or wider); fruit a red pome

............ ............ ............ ............ ............ ............ ............ ............ ..........54 Inflorescence paniculate (longer than wide); fruit various (see below), but not as above.

............ ............ ............ ............ ............ ............ ............ ............ ............ 55 Leaves stipulate; flowers bright white; fruit an aggregate of 5 follicles

............ ............ ............ ............ ............ ............ ............ ............ ............ 55 Leaves lacking stipules; flowers cream or yellow; fruit either a drupe or an inflated membranaceous capsule.

............ ............ ............ ............ ............ ............ ............ ............ ............ ..56 Fruit a drupe

............ ............ ............ ............ ............ ............ ............ ............ ............ ..56 Fruit an inflated membranaceous capsule