1 Petals absent (only sepals present, these connate and tubular); carpels 5, whorled, each expanding into a stalked and papery structure which bears 1-4 pea-sized seeds along its margins; tree; leaves 10-40 cm wide, 3-5 lobed, the lobes acute, the margins entire; [subfamily Sterculioideae]

1 Petals present; carpels 1, 5, or many, united or separate, but not as above; tree, shrub, or herb; leaves< 15 cm wide, lobed or unlobed, but if lobed then also serrate.

  2 Epicalyx of bracts absent (no whorl of bract-like structures subtending the calyx in each flower; Malachra inflorescences subtended by boat-shaped bracts, but individual flowers lacking an epicalyx).

    3 Stamens 3 or 5; [subfamily Byttnerioideae].

      4 Flowers solitary or in 2-3-flowered fascicles in leaf axils; petals hooded, caducous; capsules with prickles 0.3-0.5 mm long

      4 Flowers in capitate or umbellate clusters of > 4 flowers; petals flat, persistent; capsules smooth or hairy.

        5 Ovary with 5 carpels and 5 styles; capsule with 5-10 seeds; corolla pink, purple, or white

        5 Ovary with 1 carpel and 1 style; capsule with 1 seed; corolla orange to yellow

    3 Stamens >10.

          6 Stamens free.

             7 Tree; fruit a woody drupe, the peduncle adnate for half of its length to a thin, curved, leafy bract; [subfamily Tilioideae]

             7 Herb or shrub (sometimes a small tree in Grewia); fruit a capsule OR a fleshy drupe lacking a conspicuous leafy bract; [subfamily Grewioideae].

               8 Plants shrubs or small trees; fruit a drupe (purple and somewhat fleshy when ripe); [subfamily Grewioideae, tribe Grewieae].

               8 Plants herbs or shrubs; fruit a capsule [subfamily Grewioideae, tribe Apeibeae].

                 9 Leaves rounded or subcordate at base, acute at apex; fruit much longer than broad, unarmed

                 9 Leaves cuneate at base, acuminate at apex; fruit subglobose, with hooked spines

          6 Stamens united into a staminal column adnate to the corolla at its base; [subfamily Malvoideae; tribe Malveae].

                   10 Inflorescence subtended by (mostly) sessile boat-shaped bracts, these prominently veined and often at least somewhat deltoid or cordate in shape; stems puberulent or hispid (not viscid, but densely stellate in M. capitata)

                   10 Inflorescence not subtended by sessile, boat-shaped bracts; stems glabrous to pubescent (viscid or not).

                     11 Seeds 2 or more per carpel.

                       12 Fruit inflated, papery, mericarps lacking a beak; [s. FL and s. TX in our area]

                       12 Fruit not inflated, mericarps with a beak; [collectively widespread]

                     11 Seed 1 per carpel.

                          13 Leaves unlobed or lobed (if lobed , < 4/5’s of the way to the midrib and the lobes broad).

                            14 Flowers many in a terminal panicle; corolla white; style branches filiform, the stigmatic surface elongate along the inner side of the branches; leaves >10 cm wide, deeply 5-9-lobed; plants 1-2 m tall

                            14 Flowers solitary or a few in leaf axils (or many in a terminal panicle in Sida hermaphrodita); corolla blue-purple, yellow, or white; style branches truncate, the stigmatic surface terminal and capitate; leaves < 2 cm wide, unlobed (or leaves > 10 cm wide and deeply 3-7-lobed in Sida hermaphrodita); plants < 1 m tall (or 1-4 m tall in Sida hermaphrodita).

                              15 Corolla blue to purple; lateral walls of the carpels disintegrating at maturity of the fruit

                              15 Corolla yellow or white; lateral walls of the carpels persistent

                                16 Leaves deeply palmately lobed; plants 1-2 (-4) m tall; petals white

                                16 Leaves unlobed; plants 0.2-1 m tall; petals yellow

  2 Epicalyx of bracts (immediately subtending the calyx) present.

                                  17 Fruit a loculicidal capsule, or fleshy and berry-like, or leathery and indehiscent.

                                    18 Fruit fleshy and berry-like or leathery and indehiscent; [subfamily Malvoideae].

                                       19 Corolla open at anthesis; involucel bracts 3-5; fruit leathery, indehiscent (appearing almost woody); [tribe Gossypieae]

                                       19 Corolla closed (or nearly so) at anthesis; involucel bracts 7-12; fruit fleshy and berry-like, eventually dehiscing; [tribe Hibisceae]

                                    18 Fruit a loculicidal capsule.

                                         20 Calyx spathe-like, soon falling after anthesis; capsules elongate and long-tipped; [subfamily Malvoideae; tribe Hibisceae]

                                         20 Calyx persistent, radially symmetrical; capsules typically rounded or globose, not long-tipped.

                                           21 Style branches short, erect, and clavate (club-shaped); epicalyx bracts 3, large, foliaceous, and incised (Gossypium) or 6-9 (Cienfuegosia); seeds hairy (inconspicuously so in Cienfuegosia drummondii) or densely wooly with long white fibers (Gossypium); [subfamily Malvoideae; tribe Gossypiae]

                                             22 Plants smaller herbs (sometimes smaller subshrubs, stems rarely exceeding 0.5 m in height), decumbent to erect; seeds 2-4 mm long, inconspicuously (C. drummondii) or conspicuously (C. yucatanensis) hairy; epicalyx bracts 6-9 (if longer, as in C. drummondii, then not concealing the calyx)

                                             22 Plants larger shrubs, 1-2 m tall, stems primarily erect; seeds 8-10 mm long, densely wooly; epicalyx bracts 3 (these large, incised, and often concealing the calyx)

                                           21 Style branches elongate, spreading; epicalyx bracts 5-15, linear to lanceolate and untoothed; seeds sometimes pubescent but not with long white fibers; [subfamily Malvoideae; tribe Hibisceae].

                                               23 Stipules conspicuous, enclosing the twig, early deciduous but the scars forming conspicuous annular rings encircling the stem (usually enclosing the terminal bud); fruit not spiny (but densely pubescent); [non-natives, c. and s. FL]

                                               23 Stipule scars inconspicuous, not forming an annular ring encircling the stem; [natives and non-natives, widespread].

                                                 24 Locules of the fruit several-seeded; capsule longer than broad, the apex pointed or rounded; petals yellow, white, red, or pink (if pink, then > 4 cm long, or the plant a shrub)

                                                 24 Locules of the fruit 1-seeded; capsule depressed-globose, indented at the apex; petals pink, 2-4 cm long

                                  17 Fruit a schizocarp, consiting of radially disposed, 1- to several-seeded, dry carpels that split apart at maturity.

                                                    25 Bracts of the epicalyx 5 or more.

                                                      26 Shrubs or woody herbs, with leaves not basally disposed; flowers in axils of well-developed leaves; fruit spiny (except Pavonia hastata, which usually has puberulent fruit); [of SC southward]; [subfamily Malvoideae; tribe Hibisceae].

                                                        27 Bracts of the epicalyx 5-15, distinct; fruit with 0-3 spines per carpel; leaves lacking foliar nectaries

                                                        27 Bracts of epicalyx 5, fused basally; fruit covered with numerous glochidiate spines; leaves with 1-3 foliar nectaries (glands) on the undersurface (at the base of the central veins)

                                                      26 Herbs, with leaves basally disposed; flowers in terminal bracteates spikes or racemes; fruit lacking spines; [collectively widespread]; [subfamily Malvoideae; tribe Malveae].

                                                          28 Plant 1.5-3 m tall, usually unbranched; flowers 6-10 cm across

                                                          28 Plant 0.5-1.2 m tall, branched; flowers 2-3 cm across

                                                    25 Bracts of the epicalyx 2-3; [subfamily Malvoideae; tribe Malveae].

                                                            29 Ovules and seeds 2 or more per carpel.

                                                              30 Herb 0.5-2.5 m tall, upright; petals 2-3 cm long, pink-purple; carpels not beaked at the tip

                                                              30 Herb to 0.5 m tall, prostrate to ascending; petals 0.3-0.5 cm long, orange-red; carpels beaked at the tip

                                                            29 Ovules and seeds 1 per carpel.

                                                                 31 Leaf blades 1.5-8× as long as wide.

                                                                   32 Style branches truncate, the stigmatic surface terminal and capitate

                                                                 31 Leaf blades orbicular, about as wide as long.

                                                                     33 Leaves unlobed or shallowly lobed

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 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

                                                 24 Fruit a 5-seeded drupe

                                               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