1 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

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

  2 Basal leaves 2-lobed, pinnately lobed, or palmately lobed (not considering cordate, hastate, or auriculate leaf bases as “lobed”).

    3 Basal leaves 2-lobed, hinged between the lobes, each lobe with stiff, marginal, eyelash-like bristles; [Coastal Plain of NC and SC, rarely planted and weakly naturalized elsewhere]

    3 Basal leaves 3-many-lobed, palmately or pinnately; [collectively widespread].

      4 Leaf lobing pinnate.

        5 Gynoecium of separate pistils (each with a single carpel); fruit an aggregate

        5 Gynoecium of a single pistil (with 2, rarely more, carpels); fruit simple.

          6 Stamens many; sepals 2, petals 4; fresh plants with yellow, orange, or white milky juice

          6 Stamens 4, 5, or 6; sepals 4 or 5; petals 4 or 5.

             7 Petals 4, distinct; stamens 6

             7 Petals 5, fused; stamens 2, 4, or 5.

               8 Corolla radially symmetrical; stamens 5

               8 Corolla 2-lipped, bilaterally symmetrical or asymmetrical; stamens 2 or 4.

                 9 Corolla lobes not twisted, the flower bilaterally symmetrical; stamens 2

                 9 Corolla lobes twisted so as to make the flower asymmetrical; stamens 4

      4 Leaf lobing palmate.

                   10 Petiole attachment peltate.

                     11 Leaves < 10 cm in diameter

                     11 Leaves > 15 cm in diameter

                   10 Petiole attachment marginal.

                       12 Ovary inferior.

                          13 Petals 4; stamens 8; fruit a capsule

                          13 Petals 5; stamens 5; fruit a schizocarp of 2 mericarps.

                            14 Fruit tuberculate; leaves 3-lobed

                            14 Fruit smooth; leaves with 5 or more lobes

                       12 Ovary superior, or half-inferior by fusion of a hypanthium a part of the way up the ovary wall.

                              15 Gynoecium of separate pistils (each with a single carpel); fruit an aggregate.

                                16 Perianth of 5 green sepals and 5 colored petals.

                                  17 Carpels partly fused, arrayed in a ring of 10-20

                                  17 Carpels separate, spiral, many

                                16 Perianth of a single whorl of 3-12 petaloid sepals (the petals absent or small and rudimentary).

                                    18 Leaves 2, the single flower terminal and associated with the upper leaf; fruit an aggregate of berries

                                    18 Leaves normally > 2, flowers not as above; fruit an aggregate of achenes, utricles, or follicles

                              15 Gynoecium of a single pistil (with 1-5 carpels); fruit simple.

                                       19 Hypanthium present, partially fused or not fused to the pistil; ovary partially inferior to superior

                                       19 Hypanthium absent; ovary superior.

                                         20 Petals connate at base; leaves sharply toothed

                                         20 Petals distinct; leaves with rounded lobes or teeth.

                                           21 Corolla radially symmetrical; petals 8-12; capsule fusiform, narrowed to both ends, > 5× as long as wide

                                           21 Corolla bilaterally symmetrical; petals 5; capsule ovoid, < 2× as long as wide

  2 Basal leaves not lobed, at most serrate or crenate (and sometimes also cordate, hastate, auriculate, or peltate at the base).

                                             22 Basal leaves petiolate, the blade with a cordate, hastate, auriculate, or peltate base.

                                               23 Leaf margins entire.

                                                 24 Inflorescence a terminal and/or axillary raceme, panicle, or cyme of many small flowers; fruit an achene; perianth uniseriate, of 0, 4-5, or 6 tepals.

                                                    25 Flowers unisexual; staminate flowers 4-5 tepals, pistillate flowers lacking a perianth

                                                    25 Flowers bisexual; flowers with 6 tepals

                                                 24 Inflorescence either a terminal spike, or a 1-7-flowered terminal cyme, or of a solitary axillary or terminal flower; fruit various; perianth biseriate (of differentiated sepals and petals (except uniseriate, of 3 fused sepals in ARISTOLOCHIACEAE).

                                                      26 Flowers bilaterally symmetrical; inflorescence a terminal spike (with > 20 flowers); petals 4, usually scarious, transparent; sepals 4, green; stamens 4

                                                      26 Flowers radially symmetrical; inflorescence either of a solitary flower or of a 1-7-flowered terminal cyme; petals 5, 8-12, or 0; sepals 5 (green), 3 (brown), or 5-9 (yellow); stamens 5, 12, or many.

                                                        27 Gynoecium of separate pistils (each with a single carpel); fruit an aggregate of achenes or follicles; flowers bright yellow, either of 5-9 distinct petaloid sepals, or of 8-12 distinct petals subtended by 3-4 green distinct sepals

                                                        27 Gynoecium either of a single pistil with 6 carpels or of a single pistil with 4 carpels or of 2 nearly separate carpels; fruit a simple capsule (or deeply 2-lobed); flowers white, brown, or greenish, either of 5 fused or distinct white petals and 5 fused or distinct green sepals, or of 3 fused brown or greenish petaloid sepals.

                                                          28 Flowers brown or green, of 3 fused brown or greenish petaloid sepals (and 0 petals); carpels 6; stamens 12; leaves 4-10 cm wide

                                                          28 Flowers white, of 5 white or whitish petals and 5 green sepals; carpels 2; stamens 5; leaves 1-12 (-15) cm wide

                                                            29 Petals separate; sepals separate; plant glabrous

                                                            29 Petals fused (at least basally in Dichondra); sepals fused; carpels 2; plant pubescent.

                                                              30 Fruit a deeply 2-lobed capsule; sepals longer or ca. as long as petals; petals not undulate, fused at their bases or distal ½, the anthers maroon or brown-colored; [common, widespread in our area]

                                                              30 Fruit a fleshy berry; sepals shorter than the petals; petals undulate, fused, the anthers yellow; [rare exotic]

                                               23 Leaf margins crenate, serrate, or incised.

                                                                 31 Gynoecium of separate pistils (each with a single carpel); fruit an aggregate; perianth of 5 green sepals and 5 colored petals (or of 2 or 4 (-5) white-colored tepals in Begonia).

                                                                   32 Flowers typically with 2 or 4 (-5) white-colored tepals; leaf bases conspicuously oblique (sometimes variegated); fruit unequally or subequally 3-winged capsules; [ornamental waifs or uncommon non-natives]

                                                                   32 Flowers with 5 green sepals and 5 colored petals (not merged into tepals); leaf bases oblique or not; fruit various but not 3-winged capsules; [natives and non-natives].

                                                                     33 Carpels 10-20, partly fused, arrayed in a ring; petals white, pink, red, or purplish

                                                                     33 Carpels many, separate, spiral; petals yellow or white.

                                                                       34 Flowers lacking a hypanthium; fruit an aggregate of achenes or aggregate of follicles

                                                                       34 Flowers with a hypanthium; fruit an aggregate of drupelets or aggregate of achenes

                                                                 31 Gynoecium of a single pistil (with 1-5 carpels); fruit simple.

                                                                         35 Flowers bilaterally symmetrical; inflorescence of a solitary flower; fruit a 3-locular capsule

                                                                         35 Flowers radially symmetrical; inflorescence an umbel (or composite of umbelliform units, or a terminal panicle.

                                                                           36 Ovary superior; inflorescence a terminal panicle or terminal raceme.

                                                                              37 Inflorescence a terminal raceme; perianth of 4 green sepals and 4 white petals; fruit a silique/silicle; fresh foliage in spring and summer with a strong garlic odor; larger leaves < 10 cm in diameter

                                                                              37 Inflorescence a terminal panicle; perianth of 6 cream-colored petaloid sepals; fruit a winged achene; fresh foliage lacking a garlic odor; larger leaves typically > 30 cm in diameter

                                                                           36 Ovary inferior; inflorescence an umbel (or a composite of umbellate units); fruit a schizocarp of mericarps.

                                                                                38 Petiole attachment peltate

                                                                                38 Petiole attachment marginal (the blade cleft to the petiole.

                                                                                  39 Leaf blades longer than wide, sharply V-cleft at the base and otherwise shallowly denticulate

                                                                                  39 Leaf blades as broad or broader than long, cleft at the base and also irregularly serrate or crenate around the margin

                                             22 Basal leaves petiolate or not, with a truncate, rounded, or cuneate leaf base.

                                                                                    40 Leaves tubular, with a sutured ventral flange, erect or reclining, adapted as a pitfall for insects (flat, phyllodial leaves sometimes present as well, common in the winter in some species, such as S. oreophila)

                                                                                    40 Leaves flat, not sutured into a tubular shape.

                                                                                      41 Stem leaves opposite; perianth 5-merous, at least the corolla bilaterally symmetrical (barely so in VALERIANACEAE), or the parts curved so as to be asymmetrical (Pedicularis in OROBANCHACEAE); stamens 2, 3, or 4.

                                                                                        42 Ovary inferior; stamens 3

                                                                                        42 Ovary superior; stamens 2 or 4.

                                                                                           43 Corolla narrowly tubular, the five lobes flaring at nearly 90 degrees and nearly radially symmetrical

                                                                                           43 Corolla distinctly 2-lipped (with prominently large upper and lower corolla lobes) or hooded (the upper lip hood-like), distinctly bilaterally symmetrical, or the lobes twisted so as to make the corolla asymmetrical.

                                                                                             44 Corolla yellow, the upper lip often slightly to strongly maroon, hooded but the corolla lobes twisted so as to make the flower asymmetrical

                                                                                             44 Corolla white, lavender, or blue, 2-lipped and bilaterally symmetrical.

                                                                                               45 Sepals separate to the base or nearly so, not forming a tube

                                                                                               45 Sepals connate for at least 0.3× their length to form a tube

                                                                                      41 Stem leaves alternate; perianth radially symmetrical (less commonly bilaterally symmetrical); stamens 5, 6-8, 9, 10 (rarely 4).

                                                                                                 46 Ovary inferior (or half-inferior in Samolus).

                                                                                                   47 Perianth 4-merous; stamens 8

                                                                                                   47 Perianth 5-merous; stamens 5.

                                                                                                     48 Inflorescence an umbel; fruit a schizocarp of 2 mericarps

                                                                                                     48 Inflorescence an axillary or terminal raceme; fruit a capsule

                                                                                                 46 Ovary superior.

                                                                                                        49 Pistils many, each with a single carpel; fruit an aggregate of achenes

                                                                                                        49 Pistil 1, with 1-5 carpels; fruit simple (a legume, silique/silicle, capsule, utricle, or schizocarp of 4 nutlets).

                                                                                                          50 Corolla bilaterally symmetrical (barely so in Limosella in SCROPHULARIACEAE); stamens 2, 4, 6, 8, or 10.

                                                                                                            51 Stamens 6-8 or 10.

                                                                                                              52 Petals separate; stamens 10

                                                                                                              52 Petals fused; stamens 10 or 6-8.

                                                                                                                53 Stamens 10, monadelphous

                                                                                                            51 Stamens 2 or 4.

                                                                                                                  54 Stamens 2

                                                                                                                  54 Stamens 4.

                                                                                                                     55 [plants of coastal wetlands]

                                                                                                                     55 [plants of uplands or inland seeps or fens]

                                                                                                                       56 Flowers (and subtending bracts) red or yellow

                                                                                                                       56 Flowers purple, blue, or lavender

                                                                                                          50 Corolla radially symmetrical; stamens 5, 10, 4-6, or 9.

                                                                                                                         57 Perianth of 6 tepals; stamens 4-6 or 9; carpels 3

                                                                                                                         57 Perianth of green sepals and more brightly colored petals; stamens 5 or 10; carpels 2, 3, 4, or 5.

                                                                                                                           58 Leaves covered with sticky, gland-tipped hairs (often red), as flypaper traps for insects

                                                                                                                           58 Leaves lacking sticky gland-tipped hairs.

                                                                                                                             59 Fruit a schizocarp of 4 nutlets (ovary obviously 4-lobed in flower)

                                                                                                                             59 Fruit a capsule or silique/silicle (or utricle in Limonium in PLUMBAGINACEAE).

                                                                                                                               60 Inflorescence of a solitary, terminal flower; carpels 2-3 (-4).

                                                                                                                                  61 Corolla with a long tube and flaring corolla lobes (united > ½ its length)

                                                                                                                                  61 Corolla of separate petals or united only for a short length (< ¼ its length).

                                                                                                                                    62 Leaves serrate

                                                                                                                                    62 Leaves entire

                                                                                                                               60 Inflorescence of several to many flowers; carpels 5 (3 in Galax in DIAPENSIACEAE).

                                                                                                                                      63 Inflorescence an umbel; petals recurved, pink to almost white

                                                                                                                                      63 Inflorescence a raceme or panicle.

                                                                                                                                        64 Fruit a silique/silicle; petals 4; stamens 6

                                                                                                                                        64 Fruit either a capsule or a utricle; petals 5; stamens 5 or 10.

                                                                                                                                          65 Inflorescence a somewhat to very diffuse panicle, with 3 or more orders of branching, not giving at all the impression that the overall inflorescence is made of racemose units.

                                                                                                                                            66 Leaves entire; stamens 5; [plants of tidal marshes]

                                                                                                                                            66 Leaves serrate or crenate; stamens 10; [plants of various habitats, especially rock outcrops and bottomland forests and streambanks, never in tidal marshes]

                                                                                                                                          65 Inflorescence either a single terminal raceme (sometimes spike-like), or of 1 to several terminal and axillary racemes (these sometimes combined into a diffuse panicle, but one whose structure is clearly made up of many racemes).

                                                                                                                                               67 Inflorescence of 1-several terminal and axillary racemes, the plant typically well-branched, especially from the base; stamens 5

                                                                                                                                               67 Inflorescence of a single, terminal raceme, the plant unbranched; stamens 10 (or 5, with 5 staminodes)

                                                                                                                                                 68 Inflorescence spike-like, the flowers many (> 40), barely pedicelled; capsule 3-locular

                                                                                                                                                 68 Inflorescence a raceme, the flowers fewer (< 20) and distinctly pedicelled; capsule 5-locular

1 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

1 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head, e.g. Eryngium in APIACEAE, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.).

  2 Perianth uniseriate (represented only by undifferentiated tepals or sepals; look at the front and back of the flowers for two layers) or completely absent; flowers usually unisexual, less commonly bisexual).

    3 Inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice; fruit a 3-lobed, 3-locular capsule

    3 Inflorescence not a cyathium (and staminate or bisexual flowers with > 1 stamen; fresh plants lacking milky juice (except Stillingia in EUPHORBIACEAE); fruit various, not as above.

      4 Leaf margins toothed in some manner (serrate, dentate, crenate, etc.)

        5 Leaf teeth rounded to subacute, resembling shallow lobes, irregular, few (mostly < 6 per leaf side).

          6 Fruit a single-seeded achene or utricle; [plants of various disturbed or saline, usually sunny habitats]

          6 Fruit a 3-lobed, circumscissilely dehiscent capsule; [plants native of rich moist shaded forests or exotics in suburban woodlands]

        5 Leaf teeth sharp to crenate, not lobe-like, regular, many (mostly > 10 per leaf side).

             7 Leaf bases cuneate (or strongly oblique in Begonia, with one leaf base usually being cuneate, the other variously rounded or cordate).

               8 Flowers typically with 2 or 4 (-5) showy, white-colored tepals; leaves sometimes variegated; fruit unequally or subequally 3-winged capsules; [ornamental waifs or uncommon non-natives]

               8 Flowers cyathia, not merely bearing showy tepals; leaf not variegated but sometimes bearing darkened red or black splotches; fruit capsules, but these not conspicuously winged; [natives and non-natives, usually not ornamental]

             7 Leaf bases cordate to rounded.

                 9 Styles 3; fruit a 3-lobed, 3-carpellate capsule (1 carpel sometimes aborting); inflorescence either a terminal or leaf opposed raceme, or a dense axillary condensed cyme with conspicuous toothed bracts subtending the flowers

                 9 Styles 1 or 2; fruit either an achene or a multiple of achenes; inflorescence either an axillary dense cyme (almost a head), or an axillary spike with glomerules, or a terminal or axillary panicle.

                   10 Styles 2; inflorescence a dense axillary cyme (almost a head); fruit a multiple of achenes; plant lacking stinging hairs; [exotic plant of weedy situations]

                   10 Style 1; inflorescence an axillary spikes with glomerules, or a terminal or axillary panicle; plant either with stinging hairs or not; [plant a rare exotic (Boehmeria nivea) or a native of moist forests (Boehmeria cylindrica, Laportea)]

      4 Leaf margins entire.

                     11 Ovary inferior (flowers epigynous, the ovary sitting below the perianth and androecium) or half-inferior (perigynous, the ovary sitting level with the remaining floral parts).

                       12 Leaf base cordate; calyx 3-lobed, fused into a bilaterally symmetrical, curved brown or yellowish tube; fruit a capsule

                       12 Leaf base cuneate, rounded, or truncate; calyx of 3-4-5 distinct sepals, radially symmetrical, white or yellow; fruit a dry, nutlike drupe or an achene.

                          13 Leaves subsessile or very short petiolate, elliptic or narrowly elliptic, broadest near the middle; [native]

                          13 Leaves distinctly petiolate, rhombic, widest near the base; [rarely naturalized exotics].

                            14 Inflorescence of a single axillary flower

                            14 Inflorescence terminal, spikelike

                     11 Ovary superior (flowers hypogynous, the ovary sitting above the perianth and androecium).

                              15 Inflorescence a leaf-opposed spike or raceme, the inflorescence arising opposite of stem leaves (except Saururus, whose spikelike racemes are leaf-opposed and/or terminal); flowers visually white from white petaloid sepals, white bracts, or white stamens.

                                16 Sepals present, 4 or 5; petaloid, white; carpels 1 to many (-12); stamens 4 to many (-25); fruit a berry or an apically 2-lobed achene (as in Petiveria); leaf bases cuneate or rounded (but not cordate); [Eudicots].

                                  17 Sepals 4; carpels 1; fruit subglobose berries or apically lobed achenes

                                  17 Sepals 5; carpels 5-12, distinct; fruit an oblate berry

                                16 Sepals absent; carpels 3-4; stamens 2-6 (-8); fruit a capsule, a 1-seeded drupe, or a schizocarp of 3-4 mericarps; leaf bases cordate or subcordate; [Basal Angiosperms].

                                    18 Fruit a 1-seeded drupe; stamens 2; plants terrestrial or epiphytic

                                    18 Fruit a capsule or schizocarp with 3-4 mericarps; stamens 3 or 6-8; plants terrestrial

                              15 Inflorescence not leaf opposed, instead arising with stem leaves (axillary) or terminal, the inflorescence not spikes nor racemes, instead either simpler (single axillary or glomerules of flowers) or more complexly branched (terminal or axilary panicles or terminal complex cymes); flowers white, reddish, scarious, or greenish.

                                       19 Stipules tubular, sheathing (= ocreae); flowers subtended by tubular, sheathing bracteoles (= ocreolae); nodes usually prominently swollen; perianth usually of 5-6 white to pink tepals

                                       19 Stipules not tubular or sheathing; flowers not subtended by ocreolae; nodes not swollen; perianth absent or of 3-5 sepals.

                                         20 Inflorescence a terminal involucrate cluster; flowers bisexual; stamens 9

                                         20 Inflorescence axillary, or a terminal panicle or raceme that is not involucrate; stamens 3-6.

                                           21 Ovary 3-locular; styles 3, each bifid; fruit a capsule, with 6 seeds

                                           21 Ovary 1-locular; styles 1-3, not bifid; fruit a utricle or achene (1-seeded).

                                             22 Sepals petaloid, pink and relatively conspicuous (although the sepals ca. 1-3 mm in length); plants prostrate to somewhat ascending annuals; leaves opposite or nearly whorled; achenes muricate

                                             22 Sepals not petaloid, inconspicuous, green or greyish in color; plants prostrate or erect, annual or perennial; leaves alternate OR either alternate or opposite (Amaranthaceae); achenes variously textured (smooth or textured, sometimes reticulate or verrucose, but rarely muricate).

                                               23 Styles 1, stigma 1; flowers unisexual

                                               23 Styles 1-3, if style 1, then stigmas 3; flowers bisexual or unisexual.

                                                 24 Tepals acute, scarious

                                                 24 Tepals usually blunt, herbaceous

  2 Perianth biseriate (represented by differentiated whorls of sepals and petals, the sepals usually green or drab in color, the petals often brightly colored); flowers nearly always bisexual (there are exceptions).

                                                    25 Ovary inferior (epigynous) or half-inferior (perigynous).

                                                      26 Petals connate (at least basally, often the lower half of corolla).

                                                        27 Inflorescence a leaf-opposed, dense, cylindrical spike

                                                        27 Inflorescence not a dense, leaf-opposed spike, instead a terminal head or variously axillary or terminal (the flowers solitary or not, but not in a dense spike).

                                                          28 Flowers yellow; stamens numerous (15+), monomorphic or heteromorphic (inner and outer of differing length), conspicuously exerted from the flowers, often surpassing the ovary; leaves basally lobed or unlobed (often a mix in M. floridana and M. oligosperma)

                                                          28 Flowers blue or white; stamens fewer (usually < 10), monomorphic, if exerted, the ovary usually still apparent; leaves unlobed.

                                                            29 Leaves toothed; flowers blue to white

                                                            29 Leaves entire; flowers white

                                                      26 Petals distinct.

                                                              30 Petals 5; stamens 5; inflorescence a head; fruit a schizocarp of 2 mericarps

                                                              30 Petals 4 7; stamens 6 or more; inflorescence various, not a head; fruit a capsule.

                                                                 31 Petals 4-7; stamens 1× or 2× as many as the petals, 4-7, 8, 10, 12, or14; leaves herbaceous in texture

                                                                 31 Petals 5 (or sometimes doubled in horticultural forms); stamens 6-40 (or more); leaves fleshy in texture

                                                    25 Ovary superior (hypogynous).

                                                                   32 Corolla bilaterally symmetrical (zygomorphic), petals connate, at least basally (except distinct in VIOLACEAE); fruit a capsule or legume (the capsule conspicuously spiny in Krameria).

                                                                     33 Petals distinct, 5; carpels 3; fruit a 3-loculed capsule

                                                                     33 Petals connate (at least basally), 4, 5, 6, 7, or 8; carpels 1, 2, 4, 5, or 6 (rarely 3 in Reseda in RESEDACEAE); fruit a legume or 1-, 2-, or 5-loculed capsule (except a 1-seeded indehiscent pod in Krameria in KRAMERIACEAE).

                                                                       34 Stamens 6-10 (-25), more than the number (4 or 5) of petals and the number (4 or 5) of the sepals; fruit a legume or a 1-6-carpellate capsule.

                                                                         35 Stamens fused, monadelphous or diadelphous.

                                                                           36 Stamens 10, monadelphous or diadelphous; fruit a legume

                                                                         35 Stamens distinct.

                                                                              37 Carpel 1; fruit a legume

                                                                              37 Carpels 3-6; fruit a capsule

                                                                       34 Stamens 4-5, less than or the same as the number (5) of the petals; fruit a 2-5-carpellate capsule.

                                                                                38 Pistil 5-carpellate; capsule 5-locular, explosively dehiscent; inflorescence of axillary, small clusters of flowers

                                                                                38 Pistil 2-carpellate; capsule 2 locular, opening gradually or not at all; inflorescence a terminal spike, raceme or panicle (or solitary, axillary flowers in Chaenorrhinum in PLANTAGINACEAE and Krameria in KRAMERIACEAE).

                                                                                  39 Fruit 1-seeded, indehiscent; sepals petaloid, red-purple; petals dimorphic, the upper 3 long-clawed, the lower 2 small, thickened, and glandlike; fruit a spiny pod

                                                                                  39 Fruit > 2-seeded, dehiscent; sepals sepaloid, green; petals not dimorphic.

                                                                                    40 Stamens 5; corolla not spurred; capsule septicidal; pubescence of the stem and leaves either gland-tipped or dendritically branched

                                                                                    40 Stamens 4; corolla with a distinct spur or sac at the base between the the 2 lower calyx lobes (except not spurred in Digitalis and Schwalbea); capsule loculicidal (only at the summit in Antirrhinum and Chaenorrhinum, and septicidal in Schwalbea); pubescence of the stem and leaves neither gland-tipped (except in Antirrhinum and Chaenorrhinum) nor dendritically branched.

                                                                                      41 Capsule septicidal; corolla not spurred

                                                                                      41 Capsule loculicidal; corolla spurred (except Digitalis)

                                                                   32 Corolla radially symmetrical (actinomorphic), petals connate or distinct; fruit various (including capsules).

                                                                                        42 Plants herbaceous vines, fleshy and mucilaginous, the leaves variously orbicular, ovate, cordate or sometimes elliptic; fruit utricles (small sacs surrounding an achene), partly to completely enclosed in the persistent, dry to somewhat fleshy perianth; sepals 2

                                                                                        42 Plants not herbaceous vines, the leaves variously shaped; fruit various, but never utricles; sepals 4 or more.

                                                                                           43 Petals distinct (flowers apopetalous); stamens 5-many (4 or 5 in Capraria).

                                                                                             44 Pistils 4-10 (each 1-carpellate) in a ring, these sometimes fused basally, each with its own style/stigma; fruit either an aggregate of achenes or follicles or a 5 (-7) locular capsule.

                                                                                               45 Pistils 5 (-7); inflorescence a compound terminal cyme.

                                                                                                 46 Fruit an aggregate of follicles; leaves fleshy in texture; inflorescence; leaves entire of sparsely and coarsely serrate, with < 12 points per leaf; [plants primarily of dry habitats]

                                                                                                 46 Fruit a 5 (-7) locular capsule; leaves membranaceous in texture; leaves serrate, with > 20 points per leaf; [plants of wet habitats]

                                                                                               45 Pistils many; inflorescence of solitary flowers, or diffuse.

                                                                                                   47 Leaves cuneate at the base; flowers in a diffuse inflorescence

                                                                                                   47 Leaves cordate at the base; flowers solitary, on long pedicels

                                                                                             44 Pistil 1, with 1-to many carpels (in many MALVACEAE, the carpels loosely united in a ring [of more than 5] around the single style/stigma); fruit either a 1-, 2-, 3-, 5-, 6-, or 10-locular capsule, or a silique/silicle, or a ring of mericarps.

                                                                                                     48 Petals 4; sepals 4; stamens 6; fruit a silique/silicle

                                                                                                     48 Petals 5 (rarely 4 or 6); sepals 5 (rarely 4 or 6); stamens 4, 5 (or multiples of 5), 6, or 12; fruit a capsule or a ring of mericarps.

                                                                                                        49 Stamens many, connate into a staminal tube; carpels 5-many; fruit a capsule or ring of mericarps; leaves usually serrate or crenate

                                                                                                        49 Stamens (4-) 5-many, distinct (not forming a staminal tube); carpels 2-5; fruit a capsule; leaves entire (serrate in Croton in EUPHORBIACEAE, distally serrate in Capraria in SCROPHULARIACEAE).

                                                                                                          50 Flowers unisexual; leaf vestiture of peltate scales and/or stellate hairs

                                                                                                          50 Flowers bisexual; leaf vestiture (if present) simple or stellate.

                                                                                                            51 Flowers 6-merous (the petals and sepals 6, the stamens 6 or 12); corolla pink or purplish (rarely white); fruit a septicidal capsule

                                                                                                            51 Flowers 5-merous (the petals and sepals 5, stamens 5 or various multiples of 5); corolla white, yellow, reddish (including pinkish), or blue; fruit a loculicidal or septicidal capsule.

                                                                                                              52 Stamens 5 ; corolla yellow or blue; capsule either 10-locular and septicidal (Linum) or 1-locular (with 3 carpels) and loculicidal.

                                                                                                                53 Capsule 10-locular (with 5 carpels) and septicidal (splitting at the septa, opening at the top)

                                                                                                                53 Capsule 1-locular (with 3 carpels) and loculicidal (splitting along outer edges, not only at the top)

                                                                                                              52 Stamens (4-) 10, 15, 20, 30 (-many); corolla white, pink, yellow, or reddish; capsule 2-, 3-, 5- (-10)-locular, loculicidal.

                                                                                                                  54 Leaf margins distally serrate, the surfaces punctate-glandular and also with internal oil-secreting cavities; corolla white (the inside sometimes with scattered purple spots); [s. FL and s. TX only in our flora area]

                                                                                                                  54 Leaf margins entire, serrate, or crenate, lacking punctate-glands and internal oil-secreting cavities; corolla white, pink, yellow, or reddish; [collectively widespread, including s. FL and s. TX].

                                                                                                                     55 Stamens (5-) 10, 15, 20, 30 (-many); corolla yellow or reddish; filaments not densely villous basally, the anthers the anthers not conspicuously tubular and lacking apical pores; capsule 3 (-10)-locular, loculicidal

                                                                                                                     55 Stamens 10; corolla white or pink; filament bases dilated basally and densely villous, the anthers tubular with conspicuous apical pore dehiscence; capsule 5-locular

                                                                                           43 Petals fused (flowers sympetalous, this includes salverform and tubular flowers); stamens (4-) 5 (-7).

                                                                                                                       56 Plants herbaceous vines, fleshy and mucilaginous, the leaves variously orbicular, ovate, cordate or sometimes elliptic; fruit utricles (small sacs surrounding an achene), partly to completely enclosed in the persistent, dry to somewhat fleshy perianth; sepals 2

                                                                                                                       56 Plants not with the above combination of characters, if herbaceous vines then fruit not utricles and sepals 4 or more.

                                                                                                                         57 Pistils 2, united only by the style and stigma; fruit a schizocarp of 2 follicles (often single by abortion); plant with milky juice when fresh; leaves entire; inflorescence an umbel

                                                                                                                         57 Pistil 1 (of 2 or 3 fused carpels); fruit a capsule, drupe, or a schizocarp splitting into 4 nutlets; plant lacking milky juice; leaves entire or serrate; inflorescence various (but not an umbel).

                                                                                                                           58 Ovary slightly to deeply 2-4-lobed (entire or shallowly lobed in Tiquilia and HELIOTROPIACEAE); fruit a schizocarp of 4 mericarps or a drupe; [BORAGINALES].

                                                                                                                             59 Ovary deeply 4-parted; style gynobasic or terminal.

                                                                                                                               60 Style gynobasic (originating from the base of the ovary's lobes); ovary slightly to deeply lobed; fruit a schizocarp of 4 mericarps

                                                                                                                               60 Style terminal (originating from the apex of the ovary), twice-cleft into 4 branches, each of which then terminates in a stigma; ovary slightly lobed; fruit a drupe with a glutinous mesocarp (or if lacking, a nut)

                                                                                                                             59 Ovary slightly 2-4-lobed, or not at all lobed; style terminal or reduced to a sessile terminal stigma.

                                                                                                                                  61 Plants usually strongly gray or white-colored and villous, growing in short, suffrutescent mounds or mats; leaves densely pubescent (hairs densely appressed adaxially, tomentose abaxially); inflorescence of solitary flowers or extra-axillary, never scirpioid; corolla lavender or whitish-lavender, the lobes 1.8-3.0 (-4.5) mm long, broadly rounded; [s. TX, westward; primarily of the Trans-Pecos region]

                                                                                                                                  61 Plants variously glabrous or pubescent (sometimes villous), usually herbaceous, occasionally suffrutescent and mound or mat-forming; inflorescence variously elongate or racemose, often scirpioid (curved or coiled on one side of the inflorescence axis; e.g., Heliotropium), occasionally solitary (e.g., Euploca, in part; although in this case the leaves of the shrubby Euploca are significantly narrower); corolla variously colored (including lavender); [plants collectively widespread, including TX]

                                                                                                                           58 Ovary not lobed; fruit a capsule or berry.

                                                                                                                                    62 Leaves scale-like, 1-4.5 mm long, appressed to the stem; petals 4; stamens 4

                                                                                                                                    62 Leaves larger (or only 2-8 mm long in Pyxidanthera in DIAPENSIACEAE, but then spreading); petals 5-7; stamens 5-7.

                                                                                                                                      63 Plant a creeping subshrub (keyed here as a failsafe); leaves either 0.2-0.8 cm long and acicular, or 2-10 cm long and broadly ovate or elliptic.

                                                                                                                                        64 Leaves 0.2-0.8 cm long and acicular

                                                                                                                                        64 Leaves 2-10 cm long and broadly ovate or elliptic

                                                                                                                                      63 Plant an herb, erect or sprawling; leaves > 1.5 cm long.

                                                                                                                                          65 Leaves cordate at the base; plant a twining vine

                                                                                                                                          65 Leaves cuneate to rounded at the base; plant an erect, sprawling, or reclining herb (twining in Solanum dulcamara in SOLANACEAE).

                                                                                                                                            66 Inflorescences (solitary or of several flowers) terminal on the stem.

                                                                                                                                               67 Calyces tubular, conspicuously 5-ribbed and bearing numerous stalked, capitate-glands

                                                                                                                                               67 Calyces not as above, flowers typically campanulate (not salverform), if tubular then not also 5-ribbed and capitate-glandular.

                                                                                                                                                 68 Corolla lobes longer than the fused corolla cup, blue, pink, or white; styles 2; herbage lacking stipitate glands; fresh plants not aromatic.

                                                                                                                                                   69 Flowers in axillary cymes; capsule subglobose; leaves 2-12 cm long

                                                                                                                                                   69 Flowers solitary or paired in the leaf axils; capsule cylindrical; leaves 0.5-8 cm long

                                                                                                                                                 68 Corolla lobes very short, much shorter than the corolla cup or tube, sometimes barely perceptible and represented only by teeth on the edge of the corolla limb, white or pink; style 1; herbage often with stipitate glands; fresh plants often rankly aromatic

                                                                                                                                            66 Inflorescences (of solitary or several flowers) axillary or lateral on the stem.

                                                                                                                                                     70 Flowers sessile or very-short pedicelled, solitary in the leaf axils.

                                                                                                                                                       71 Stamens alternate with the corolla lobes; flower ca. 10 mm in diameter

                                                                                                                                                       71 Stamens opposite the corolla lobes; flower ca. 1 mm in diameter

                                                                                                                                                     70 Flowers either solitary and obviously pedicelled, or several in an axillary or lateral inflorescence.

                                                                                                                                                         72 Calyces tubular, conspicuously 5-ribbed and bearing numerous stalked, capitate-glands

                                                                                                                                                         72 Calyces not as above, flowers typically campanulate (not salverform), if tubular then not also 5-ribbed and capitate-glandular.

                                                                                                                                                            73 Corolla lobes longer than the fused corolla cup, blue

                                                                                                                                                            73 Corolla lobes very short, much shorter than the corolla cup or tube, sometimes barely perceptible and represented only by teeth on the edge of the corolla limb, white, yellow, pink, various other colors (rarely including blue).

                                                                                                                                                              74 Fruit a capsule, 4-seeded

                                                                                                                                                              74 Fruit a berry or capsule, many-seeded

1 Cauline leaves palmately compound.

  2 Cauline leaves essentially sessile, and also palmately cleft to the base, and further lacerately divided into linear or oblanceolate segments

  2 Cauline leaves petiolate, with 3-5, sessile or petiolulate, ovate, elliptic, or obovate leaflets (these serrate and sometimes with additional lobes).

    3 Inflorescence a spherical umbel of many flowers; fruit a drupe with 2-3 seeds; stem leaves 3-5

      4 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

      4 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

    3 Inflorescence of single terminal flowers on the 1-several branches; fruit an aggregate of achenes; stem leaves 3

1 Cauline leaves simple.

        5 Inflorescence an involucrate head subtended by phyllaries, heads solitary or many, variously arrayed in secondary inflorescences; fruit a cypsela

        5 Inflorescence various, but not as above; fruit various, not as above (sometimes the flowers tightly grouped, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.).

          6 Fruit a 3-lobed, 3-locular capsule; inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice

          6 Fruit various, not as above; inflorescence not a cyathium (and staminate or bisexual flowers almost always with > 1 stamen); fresh plants lacking milky juice.

             7 Leaves succulent, the terminal whorls closely juxtaposed; pistils 4-5; fruit an aggregate of follicles

             7 Leaves herbaceous, thin in texture, whorls separated; pistil 1, of 2-5 fused carpels; fruit a capsule, achene, or drupe.

               8 Larger whorled leaves on a plant < 10 mm wide [some taxa keyed here and under the second lead].

                 9 Inflorescence a cymule, either axillary, or axillary and terminal; ovary inferior.

                   10 Leaves markedly variable in shape or size in each whorl; fruit a capsule; petals 5

                   10 Leaves similar in size and shape in each whorl; fruit dry or fleshy, indehiscent; petals (3-) 4

                 9 Inflorescence a terminal raceme, panicle, spike, cyme, corymb, or umbel; ovary superior.

                     11 Corolla bilaterally symmetrical, the petals connate; carpels 2; stamens 4, 6, or 8.

                       12 Stamens 4; corolla blue or almost white

                     11 Corolla radially symmetrical, the petals separate; carpels 2, 3, or 5; stamens 5, 10, or many.

                          13 Inflorescence an axillary umbel; leaves narrowly linear and more than 10× as long as wide, > 20 mm long and < 2 mm wide; whorls of 3-6 leaves

                          13 Inflorescence a terminal cyme, raceme, panicle, or umbel; leaves as above, or broader in shape, narrower, or shorter; whorls of 3-16 leaves.

                            14 Inflorescence a terminal cyme or umbel; corolla white; carpels 5.

                              15 Leaves narrowly linear, 12-16 in each whorl; stamens 5

                              15 Leaves ovate or obovate, 3 (-4) in each whorl

                            14 Inflorescence a terminal raceme or panicle; corolla reddish, maroon, or yellow.

                                16 Corolla reddish or maroon

                                16 Corolla yellow

               8 Larger whorled leaves on a plant > 10 mm wide.

                                  17 Inflorescence a spike; perianth absent; fruit a drupe

                                  17 Inflorescence various, but not a spike; perianth present; fruit various, but not a drupe.

                                    18 Inflorescence of terminal involucrate clusters; perianth of 6 tepals; fruit an achene; stamens 9; [plants of very dry habitats]

                                    18 Inflorescence various, but not as above; perianth of 2 whorls (the calyx often obsolete in Galium in RUBIACEAE), 3-, 4-, 5-, 6-, or 7-merous; stamens 2-7; [plants of dry-mesic to very wet habitats].

                                       19 Fruit dry or fleshy, indehiscent; petals (3-) 4; ovary inferior

                                       19 Fruit a capsule or follicle, dehiscent; petals 4-7; ovary superior.

                                         20 Inflorescence an umbel; fresh plants with milky juice

                                         20 Inflorescence not an umbel; fresh plants with clear juice.

                                           21 Corolla pink-purple, 6-merous, the petals separate and borne on the edge of a hypanthium; stamens 8, 10, or 12; [plants of wetlands]

                                           21 Corolla white, yellow, or greenish, 4-, 5-, or 7-merous, the petals fused at least basally into a tube (falling as a unit), not on a hypanthium; stamens 2, 4, 5, or 7; [plants of mesic habitats].

                                             22 Stamens 2; corolla bilaterally symmetrical

                                             22 Stamens 4, 5, or 7; corolla radially symmetrical.

                                               23 Petals yellowish-white, with prominent green streaks; biennial or monocarpic plant, 10-30 dm tall when fertile; leaves 15-35 cm long

                                               23 Petals white or yellow; perennial plants, 1-15 dm tall; leaves 1-15 cm long.

                                                 24 Leaves punctate; stem without swollen nodes

                                                 24 Leaves not punctate; stem with swollen nodes