1 Plant a woody vine; leaves simple; [subfamily Aralioideae; tribe Schefflereae]

1 Plant an herb, shrub, or tree (if a partially scandent shrub, then the stems also with conspicuous recurved prickles as in Eleutherococcus trifoliatus); leaves simple or compound.

  2 Leaves simple, peltate or cordate, roundish (if lobed, with 3-5 rounded lobes), 0.3-10 cm wide; rhizomatous, creeping herbs; [subfamily Hydrocotyloideae]

  2 Leaves either compound OR simple and palmately lobed and > 10 cm wide (the lobes 5-15 per leaf); herbs, shrubs, or trees.

    3 Leaves simple, palmately-lobed; [subfamily Aralioideae; tribe Schefflereae].

      4 Leaves 5-7-lobed (the lobes not themselves sublobed); tree, the branches armed with prickles

      4 Leaves 7-15-lobed (the lobes themselves either sublobed or not); robust herb to shrub, the branches unarmed.

        5 Leaves 7-9-lobed (the lobes not sublobed); ovary 5- or 10-carpellate; leaf blades glabrous beneath at maturity

        5 Leaves 9-15-lobed (some of the lobes sublobed); ovary 2-carpellate; leaf blades densely pubescent beneath at maturity

    3 Leaves compound.

          6 Leaves 1× palmately compound, leaflets 3-7; leaves 3-5 in a whorl at the summit of the stem (Panax) or many, clustered on spur shoots (Eleutherococcus); inflorescence of a single, simple umbel borne terminally on the stem; fruit red to yellow (Panax), purple or black (Eleutherococcus) or orange (Heptapleurum).

             7 Plant non-native shrubs or trees (sometimes partially epiphytic or scandent); with or without stem prickles; fruit black, dark purple, or orange; [subfamily Aralioideae; tribe Schefflereae].

               8 Plant a shrub (to 7 m tall), with prominent stem prickles; fruit black or dark purple when ripened; leaves either trifoliate (E. trifoliatus) or palmately compound and 5-foliolate (predominantly so in E. sieboldianus)

               8 Plant a shrub (to 4 m tall in H. arboricola) or tree (to 12 m tall in H. actinophyllum), lacking stem prickles; fruit orange when ripened; leaves palmately compound, usually 7-9-foliolate (occasionally with 5 or 10 leaflets, if 5, this not predominant across the plant)

             7 Plant native herbs, lacking prickles; fruit red or yellowish-green; [subfamily Aralioideae; tribe Aralieae].

                 9 Leaflets 3 (-5), sessile or subsessile, the petiolules 0-3 mm long; larger leaflets 4-8 cm long, 0.5-2.5 cm wide, averaging about 2.5× as long as wide, the apex obtuse to acute; fruit yellow-green when ripe, longitudinally winged and ribbed in ×-section; petals white (rarely tinged with pink); inflorescence nodding in bud; underground storage organ a spherical tuber

                 9 Leaflets (3-) 5, petiolulate, the petiolules (7-) 10-25 mm long; larger leaflets 6-15 cm long, 3.5-7 cm wide, averaging about 1.8× as long as wide, the apex acuminate; fruit bright red when ripe, smoothly elliptical in ×-section; petals light green; inflorescence erect in bud; underground storage organ an elongate root, this vertical or horizontal, and sometimes branched

1 Leaves evenly 2-pinnately compound

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

  2 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}

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

    3 Plant a liana, climbing by tendrils

    3 Plant a shrub or tree, not climbing.

      4 Plant unarmed.

        5 Plant a shrub, < 2.5 m tall.

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

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

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

             7 Leaflets entire

             7 Leaflets serrate.

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

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

1 Leaves either 2-3-foliolate or palmately 4-11-foliolate (all the leaflets attached at a common point).

  2 Leaves 2-foliolate; fruit a capsule, opening by a circumscissile lid

  2 Leaves either 3-foliolate or palmately or pedately 4-11-foliolate.

    3 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela

    3 Inflorescence, flower, and fruit structure various, but not with the combination of features as above.

      4 Inflorescence an umbel; ovary inferior; fruit a mericarp of 2 schizocarps

      4 Inflorescence various, usually not an umbel (sometimes an umbel in Oxalis in OXALIDACEAE); ovary superior; fruit an aggregate, legume, berry, or 2-valved capsule.

        5 Leaflets either entire or barely and very shallowly crenulate or notched at the tip (but otherwise entire).

          6 Inflorescence a spadix, surrounded by a spathe; fruit a berry; [Monocots {illogically keyed here because of the likelihood of being mistaken for a dicot}]

          6 Inflorescence a raceme or umbel, not surrounded by a spathe; fruit a capsule or legume; [Eudicots].

             7 Flowers bilaterally symmetrical; fruit a legume; [plant of uplands]

             7 Flowers radially symmetrical; fruit a 2-valved or 5-valved capsule; [plant of uplands or wetlands]

               8 Leaflets not notched at the tip; flowers white; [plants of saturated saturated or ponded wetlands]

               8 Leaflets notched at the tip; flowers pink, white, or yellow; [plants of uplands or temporarily flooded wetlands]

        5 Leaflets serrate, serrulate, or cleft.

                 9 Petals 4; stamens 6; fruit a silique

                 9 Petals 5 or more; stamens 10 or more; fruit either a legume or an aggregate of achenes or follicles

                   10 Stamens many, fused into a staminal tube; carpels 10-20, in a ring; pubescence stellate (sometimes mixed with simple hairs)

                   10 Stamens 10-many, separate, or fused but not all into a staminal tube; carpel either 1 (FABACEAE), or 3-7 in a ring (RANUNCULACEAE), or many and spirally arranged on a conical receptacle (RANUNCULACEAE or ROSACEAE)

                     11 Leaflets serrulate; flowers bilaterally symmetrical; fruit a legume; corolla variously colored, including white

                     11 Leaflets serrate; flowers radially symmetrical; fruit an aggregate of achenes or of follicles; corolla white or yellowish or greenish.

                       12 Fruit an aggregate of follicles

                       12 Fruit an aggregate of achenes (borne on a fleshy, expanded receptacle in Fragaria and some Potentilla)

                          13 Flowers lacking a hypanthium

                          13 Flowers with a hypanthium

1 Leaves 1-pinnately compound (all leaflets attached to a central rachis) or more complexly compound (with several orders of branching, some leaflets at least attached to second-order branches from the rachis).

                            14 Leaves 1-pinnately compound (all leaflets attached to a central rachis).

                              15 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela

                              15 Inflorescence, flower, and fruit structure various, but not with the combination of features as above.

                                16 Flowers bilaterally symmetrical; fruit a legume

                                16 Flowers radially symmetrical; fruit a silique/silicle, or a schizocarp of mericarps, or an achene.

                                  17 Petals 4; stamens 6; fruit a silique/silicle

                                  17 Petals 0 or 5 (if 0, the sepals petaloid); stamens 2, 4, 5, or many.

                                    18 Stamens 5; fruit a schizocarp of 2 mericarps

                                    18 Stamens 2, 4, or many; fruit an achene

                            14 Leaves more complexly compound (with 2 or more orders of branching, some leaflets at least attached to second-order branches from the rachis).

                                       19 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela

                                       19 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head subtended by bracts, but then with other features differing, such as stamens 4, or green calyx present, or petals separate, or fruit a schizocarp of mericarps, etc.).

                                         20 Leaf segments or ultimate lobes linear or lanceolate, > 2× as long as wide, < 4 mm wide.

                                           21 Inflorescence an umbel; ovary inferior; fruit a mericarp of 2 schizocarps

                                           21 Inflorescence various, but not an umbel; ovary superior; fruit an aggregate of follicles or an elongate capsule.

                                             22 Carpels 2, fused; fruit an elongate capsule; flowers bilaterally symmetrical

                                             22 Carpels 5-10 or many, separate; fruit an aggregate; flower radially symmetrical

                                         20 Leaf segments or ultimate lobes ovate or elliptic, < 3× as long as wide, > 5 mm wide.

                                               23 Inflorescence an umbel; ovary inferior; fruit a mericarp of 2 schizocarps or a 5-seeded drupe.

                                                 24 Fruit a schizocarp of 2 mericarps

                                               23 Inflorescence various, but not an umbel; fruit an aggregate of follicles or achenes, an elongate capsule, or a naked seed resembling a drupe.

                                                    25 Leaflets with < 10 ultimate ‘points’ (lobe or tooth terminations), these rounded to broadly acute, often large in comparison to the leaflet and appearing as “sublobes”; pistil 1 or 4-many.

                                                      26 Corolla bilaterally symmetrical; fruit an elongate capsule; [cultivated exotic, rarely persistent near gardens]

                                                      26 Corolla radially symmetrical; fruit an aggregate of follicles or achenes, or a naked seed resembling a drupe; [native plants of moist to dry forests and rock outcrops].

                                                        27 Leaflets 5-8 cm long, obviously longer than broad; pistil 1; fruit a naked blue seed resembling a drupe; flowers mainly 3-merous

                                                        27 Leaflets 1-6 cm long, about as long as broad if > 4 cm long; pistils 4-many; fruit an aggregate of follicles or achenes; flowers mainly 4-5-merous

                                                    25 Leaflets with >11 ultimate ‘points’ (lobe or tooth terminations), these acuminate to acute; pistils 1-8.

                                                          28 Pubescence of the stem and lower leaf surface glandular; flowers unisexual, on the same plant (monoecious); stamens 10; pistils 2, partly fused; fruit an aggregate of follicles

                                                          28 Pubescence of the stem and lower leaf surface non-glandular (or absent); flowers either bisexual (the plants hermaphroditic), or unisexual and the male and female flowers on separate plants (the plants dioecious); stamens 15 or more; pistils 1-8, separate; fruit an aggregate of follicles, a follicle, or a red or white berry.

                                                            29 Flowers bisexual (plants hermaphroditic); carpels 1-8 per flower; inflorescence a raceme, or a panicle of racemes with just a few branches; fruit an aggregate of follicles, a follicle, or a red or white berry

                                                            29 Flowers unisexual (plants dioecious); carpels 3-4 per pistillate flower; inflorescence a panicle of racemes, with numerous branches; fruit an aggregate of follicles