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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 a liana, with many leaves along the stem; sap milky; [subfamily Aroideae, tribe Caladieae] |
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]. |
 Show caption*© Michelle W., some rights reserved (CC BY), uploaded by Michelle W. 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] |
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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 milky; [rare exotic, n. FL southwards]; [subfamily Aroideae, tribe Caladieae] |
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) |
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1 Leaves 3-, 5-, to many-foliolate. |
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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 |
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11 Leaflets serrulate, crenulate, serrate, with a few coarse and jagged teeth ( spine-tipped or not), or shallowly lobed. |
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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). |
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20 Leaflets toothed; sap clear |
19 Leaves palmately compound (all the leaflets attached at a single point). |
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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 |
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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 |
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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. |
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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 |
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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. |
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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). |
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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 |
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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. |
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56 Fruit an inflated membranaceous capsule |
