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Key J3: lianas with opposite simple leaves with entire margins {add Paederia in RUBIACEAE}

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1 Fresh plants with white, milky juice; pistils 2, united only by the style and stigma; fruit a pair of linear or fusiform follicles, 5-8× as long as thick (or longer), these variously shaped (terete, compressed, or prominently 3-angled)
1 Fresh plants with clear juice; pistil 1; fruit various, but not of paired, linear follicles.
  2 Liana (sometimes a partially scandent shrub) climbing by paired, recurved spines at the nodes; fruit an accessory fruit of a utricle embedded in a leathery expanded calyx
  2 Liana climbing by twining (occasionally forming shrub-like masses); fruit either a capsule (< 3× as long as wide), paired berries, drupeaceous (Petrea in VERBENACEAE), or a schizocarp of samaras (MALPIGHIACEAE).
    3 Flowers lavender; the showy calyx persisting well after petals fall; fruit drupe-like; [ornamental waif, c. and s. FL]
    3 Flowers not lavender, instead white, yellow, orange, or red; the calyx not showy and not persisting after the petals fall; fruit a capsule (Gelsemium), paired berries (Lonicera) or a schizocarp of samaras (MALPIGHIACEAE); [collectively widespread natives and non-natives].
      4 Petals clawed (the bases noticeably thinner than the broadened tips), the corolla not tubular; fruit a schizocarp of samaras; [uncommon non-natives, c. and s. FL; in part, Heteropterys, Hiptage, and Stigmaphyllon]
      4 Petals not clawed, of similar width from base to tip, the corolla tubular; fruit capsules (Gelsemium) or paired berries (Lonicera); [widespread natives and non-natives]
        5 Flowers white, pale yellow, orange, or red, distinctly to obscurely bilaterally symmetrical; leaves widest slightly below, at, or above the middle, the apex rounded, obtuse, to broadly acute; fruit paired berries
        5 Flowers bright yellow, radially symmetrical; leaves widest well below the middle, the apex acuminate; fruit a capsule

Key J4: shrubs and subshrubs with opposite simple leaves with entire margins

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1 Plants aerial and epiphytic, hemiparasitic shrubs (usually growing out of the branches of trees)
1 Plants terrestrial, autotrophic or hemiparasitic shrubs or subshrubs.
  2 Leaves succulent, nearly as thick as wide; [brackish to saline situations]
  2 Leaves herbaceous or leathery (succulent in Borrichia), much wider than thick; [various habitats].
    3 Creeping or short subshrubs, the stems primarily prostrate (< 2 dm tall), or spreading-ascending to decumbent and < 3 dm tall (MALPIGHIACEAE, in part; Galphimia primarily erect subshrubs to 1 m tall, of TX only in our area).
      4 Petals clawed, the bases noticeably thinned compared to the broader tips; fruit schizocarps, breaking into 2-3 nutlets or 1-seeded cocci; [in part, Aspicarpa and Galphimia]
      4 Petals not clawed, of relatively similar width from base to tip; fruit various, but never schizocarps of 2-3 nutlets or 1-seeded cocci.
        5 Well-developed leaves 4-6 per stem; inflorescence a head subtended by 4 large white bracts
        5 Well-developed leaves many per stem; inflorescence of individual flowers axillary in pairs or clusters or in terminal cymes.
          6 Flowers yellow; leaves with pellucid or dark punctate glands (use at least 10× magnification)
          6 Flowers white, pale pink, or deep pink; leaves lacking sessile, punctate glands.
             7 Leaves linear; flowers pale to deep pink, 5-merous
             7 Leaves orbicular or elliptic; flowers white to pale pink, 4-merous or 5-merous
    3 Upright or scrambling shrubs, > 3 dm tall.
                 9 Scrambling shrubs, armed with recurved paired spines at the nodes (except Santalum, which can be a scrambling shrub and has red flowers producing drupe-like fruit bearing an apical circular rim).
                   10 Plants armed with recurved paired spines at the nodes; fruit ribbed, the ribs obviously glandular; petioles not 2-ribbed; flowers greenish-white to yellowish in color
                   10 Plants unarmed; fruit not ribbed, instead drupe-like and bearing a circular rim at the apex; petioles 2-ribbed; flowers red
                       12 Head flattened, either subtended by 4 large white bracts or by an involucre with >5 green phyllaries.
                          13 Head subtended by 4 large white bracts; leaves with prominently parallel-arcing secondary veins; flowers 4-merous
                          13 Head subtended by an involucre of >5 green phyllaries; leaves with venation otherwise; flowers 5-merous
                     11 Inflorescence otherwise (if terminal, the flowers not arranged in heads), either of a solitary flower, or one of a wide variety of inflorescences with flowers attached at different points along branched or unbranched axes (e.g. axillary). {add: [Lagerstroemia] LYTHRACEAE; [Rosmarinus] LAMIACEAE; [Buxus] BUXACEAE; [Exochorda] ROSACEAE; various other [see spreadsheet]}
                              15 Leaves distinctly 3-veined from the base, the 3 veins converging again at the leaf apex; [s. FL only in our area]
                              15 Leaves with prominently pinnate venation; [collectively widespread]
                                16 Leaves conspicuously glandular-punctate and aromatic; fruit a berry; ovary inferior; flowers with abundant stamens and a cup-shaped hypanthium; (partial; Mosiera, Myrcianthes, Syzygium).
                                16 Leaves not glandular-punctate and aromatic (only herbaceous Hypericum sometimes with black or transluscent leaf punctae, thus keyed instead in S1); flowers with 1-5 or 8-10 stamens; fruit not a berry, instead either a capsule (Hypericum), drupe (Cornus; Viburnum), follicle (APOCYNACEAE), or prominently ribbed and stipitate anthocarp (Pisonia).
                                  17 Fruit prominently ribbed (an anthocarp), the ribs with stipitate glands, the fruit thus usually sticky (this persisting on herbarium specimens)
                                  17 Fruit lacking prominent glandular ribs, the fruit not generally sticky.
                                    18 Fresh plants with white, milky juice; pistils 2, united only by the style and stigma; fruit a pair of linear or fusiform follicles, > 5-8× as long as thick, these variously shaped (terete, compressed, or prominently 3-angled)
                                    18 Fresh plants not exuding a white, milky latex (instead clear or not apparent); pistil 1 (or 2-5 in Hypericum); fruit various, but not of paired, linear follicles (see below).
                                       19 Flowers bright yellow; stamens many; leaves < 1.5 cm wide; fruit a capsule; leaves with pellucid or dark punctate glands (use at least 10× magnification)
                                       19 Flowers white or creamy; stamens 4-5; leaves > 1.5 cm wide; fruit a drupe; leaves lacking sessile, punctate glands.
                            14 Inflorescence either terminal, axillary or leaf-opposed, if terminal elongate (not flat-topped) or flowers solitary; if axillary then variously arranged (sometimes also solitary in the axils).
                                           21 Carpels many (> 9), either separate or fused; stamens many; perianth segments either many and undifferentiated into calyx and corolla, maroon, brown, or yellow (in CALYCANTHACEAE), or differentiated into a fleshy and persistent calyx of 5-9 sepals, and a deciduous corolla of 5-9 red (or white) petals (Punica in LYTHRACEAE).
                                             22 Fruit a wrinkled, 3-7 cm long, brown to black, elliptical aggregate of nearly spherical, large achenes; flowers solitary in axils; perianth segments many and undifferentiated into calyx and corolla, maroon, brown, or yellowish; ovary superior; branches unarmed
                                             22 Fruit a leathery, 4-15 cm in diameter, reddish, spherical berry with obpyramidal seeds surrounded by a juicy sarcotesta (pomegranate); perianth differentiated, the sepals fleshy and persistent on the fruit, the petals deciduous, 5-9, bright red to white; ovary inferior; branches typically armed with axillary spines
                                           21 Carpels 1-5 (-6), fused; stamens either 1-5 or 8-10 (except 10+ in MYRTACEAE); perianth segments 4-5 or 8, variously colored; fruit a simple capsule, drupe, or berry (including berry-like fruit); flowers 2-many, in axillary or terminal inflorescences OR sometimes solitary (MYRTACEAE, SANTALACEAE, and THESIACEAE); [Eudicots].
                                               23 Ovary inferior (flowers epigynous); corolla either absent, radially symmetrical, OR bilaterally symmetrical; fruit either a berry or a 1-seeded drupe (a berry or apically dehiscent capsule in MYRTACEAE).
                                                 24 Leaves conspicuously glandular-punctate and aromatic, evergreen and usually coriaceous; fruit a berry or apically-dehiscent capsule; flowers with abundant stamens and a cup-shaped hypanthium.
                                                 24 Leaves not both conspicuously glandular-punctate nor aromatic, membranous and deciduous; fruit a drupe or berry; flowers with 1-5 or 8-10 stamens, with or without a cup-shaped hypanthium.
                                                    25 Flowers unisexual and plants dioecious; corolla absent; pistillate flowers solitary, staminate flowers in pedunculate umbels or cymes, either terminal or axillary; fruit a 1-seeded drupe; leaves acute to acuminate at the apex
                                                    25 Flowers bisexual and plants hermaphroditic; corolla present; flowers paired, terminal or axillary, or in axillary spikes; fruit a berry; leaves rounded, obtuse, to acute (or acuminate in Lonicera maackii) at the apex
                                               23 Ovary superior (flowers hypogynous); corolla primarily radially symmetrical (zygomorphic in Citharexylum in VERBENACEAE and MALPIGHIACEAE; absent in Forestiera in OLEACEAE); fruit either a 1-4-seeded drupe, or a many-seeded berry (or berry-like fruit), or a capsule.
                                                        27 Leaves with a conspicuous mix of silvery stellate hairs (upper) and rusty colored scales (lower); ovaries bearing rusty colored scales; flowers small, yellowish and inconspicuous; [nw. PA northward]
                                                        27 Leaves glabrous or nearly so, lacking a conspicuous mix of stellate hairs adaxially and rusty scales abaxially; ovaries not bearing rusty colored scales; flowers of various size and color.
                                                          28 Stamens 8-10, of 2 different lengths in each flower; petals separate, 4-5 (-7), pink purple, 10-15 mm long; stems strongly arching, rooting at the tips; [plants of flooded to saturated wetlands]
                                                          28 Stamens either (1-) 2 (-4), or 4-5, or 10, all of the same length; petals fused (separate in RHAMNACEAE and BUXACEAE, but then < 5 mm long and white or cream), white, bright-yellow, lilac, or pink; stems erect (or at least not arching and rooting at the tips); [plants of various habitats].
                                                              30 Petals clawed (the bases much thinner than the broader tips); fruit a drupe; inflorescence a terminal raceme (Byrsonima) or axillary corymbs or umbels (Malpighia); [in part, Byrsonima and Malpighia; some vining species will grow shrub-like, but those keyed in J3; TX and FL only in our area]
                                                                 31 Fruit a loculicidal capsule, dehiscing into 3 valves; branches square in ×-section; leaves < 2 cm long; [exotic, cultivated and weakly established, of temperate areas]
                                                                 31 Fruit a drupe with 2-4 pyrenes; branches round or nearly so in ×-section; leaves > 2 cm long; [natives, of peninsular FL]
                                                            29 Petals fused (at least basally), 4-5, white, bright yellow, lilac, or pink; stamens either (1-) 2 (-4) or 10; fruit either a capsule or a 1-seeded drupe.

Key P1: herbaceous dicots with alternate, simple, and unlobed leaves on the stem

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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].
                              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].
                                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 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.
                                             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).
  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).
                                                        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.
                                                                 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
                                                                   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 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.
                                                                                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).
                                                                                    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.
                                                                                        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
                                                                                             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.
                                                                                                 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]
                                                                                             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.
                                                                                                        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).
                                                                                                                  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]
                                                                                                                                  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]

Key S1: herbaceous dicots with opposite, simple, and unlobed leaves on the stem

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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. Pycnanthemum in LAMIACEAE, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.; Carpobrotus is superficially asteroid, but heads are composed of numerous petaloid staminodia, and receptacles lack cypselae;).
  2 Leaves scale-like, stems fleshy; flowers embedded in the fleshy stem, no perianth present; [saline environments (coastal or rarely inland)].
  2 Leaves small to large; stems not fleshy (although sometimes plants generally succulent as in Sesuvium); flowers sessile or on pedicels; [collectively of many habitats, saline and not].
      4 Perianth of a single whorl (petals absent) (note that in Mirabilis in NYCTAGINACEAE the petaloid calyx is subtended by a 5-lobed fused set of involucral bracts).
        5 Leaves herbaceous, suborbicular, about as long as wide or wider than long; calyx 3- or 4-merous; stamens 4, 8, or 12.
          6 Plant ascending, with a single node (2 leaves); leaves > 6 cm long and wide; calyx 3-merous, brown to yellowish; stamens 12
          6 Plant creeping, with many nodes; leaves 3-15 mm long and wide; calyx 4-merous, yellow to greenish; stamens 4 or 8
        5 Leaves fleshy, linear, lanceolate, to broadly ovate, at least slightly longer than broad; calyx 5-merous; stamens 3, 5, or 10.
             7 Flowers axillary, sessile or nearly so, solitary or a few; petaloid sepals widely spreading, separate, usually with a subapical abaxial appendage; leaves linear to oblanceolate; stamens 5 or 30-50
             7 Flowers in terminal cymose panicles; petaloid sepals connate into a narrow tube (reminiscent of the corolla of Ipomoea), lacking subapical abaxial appendages; leaves lanceolate, elliptic, ovate, or broadly ovate; stamens 3 or 5
      4 Perianth in 2 whorls (sepals and petals both present).
               8 Plants succulent, mat-forming subshrubs; flowering heads showy and consisting of numerous petaloid staminodia; [waif, FL]
               8 Plants not as above.
                   10 Leaves distinctly 3-veined from the base, the 3 veins converging again at the leaf apex
                 9 Petals connate into a tube (at least basally); inflorescence often a head or dense terminal cyme (also axillary, or solitary on long peduncles).
                     11 Petals 5; stamens 3, 4, or 5
                       12 Upright herb; flowers in axils or terminal corymbs
                     11 Petals 4 (or 6 or 8 in Richardia in RUBIACEAE); stamens 4, 6, or 8.
                            14 Inflorescence a head or more diffuse (see below), sometimes subtended by green bracts.
                              15 Leaves serrate; corolla bilaterally symmetrical (especially the flowers near the outer edge of the head); inflorescence a head
                              15 Leaves entire; corolla radially symmetrical; inflorescence a head or more diffuse (see below).
                                16 Petals acute; flowers in terminal panicles, cymes, or panicles, or axillary; plant habit various, not simultaneously with all the characters below
                                16 Petals broadly rounded; flowers axillary, solitary; plant a diffusely branched herb with linear leaves
                                  17 Perianth of a single whorl (petals absent) or missing entirely (petals and sepals both absent).
                                    18 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
                                    18 Inflorescence not a cyathium (and staminate or bisexual flowers with > 1 stamen, except Callitriche in PLANTAGINACEAE); fresh plants lacking milky juice; fruit various, not as above.
                                       19 Flowers many, in axillary spikes, cymes, or glomerules, or in terminal spikes, heads, cymes, or panicles; leaves entire or serrate.
                                               23 Leaves entire, or with a few very obscure crenations (Iresine) or basally disposed rounded lobe-like teeth (Atriplex); plants without stinging hairs.
                                                    25 Style 1; leaves generally either longer than 30 mm, or wider than 8 mm (if linear and smaller than those dimensions, then fleshy).
                                                        27 Gynoecium either of 1 pistil (with 1 or more carpels), or of 2 pistils, united only by the style and stigma (APOCYNACEAE).
                                                              30 Leaves with pellucid punctate glands (most easily visible with transmitted light); stamens often fascicled into 3, 4, or 5 fascicles; petals yellow or pinkish
                                                                   32 Petals 3; sepals 5, dimorphic, the 2 outer sepals narrower than the 3 inner and concave sepals; stamens (3-) 5-15 (-25)
                                                                   32 Petals 4-7; sepals 4-7, normally monomorphic; stamens 4, 5, 6, 8, 10, or 12 (or sometimes rarely 2 or 3).
                                                                         35 Corolla radially symmetrical (or so slightly bilaterally symmetrical as to be mistakable as radially symmetrical); stamens as many as the corolla lobes (or 1 less in Ruellia in ACANTHACEAE, Buchnera in OROBANCHACEAE, Trichostema in LAMIACEAE, and Verbena in VERBENACEAE); carpels 2 or 3.
                                                                           36 Pistils 2, united only by the style and stigma; fruit a schizocarp of 2 1-carpellate follicles (often single by abortion); plant with milky juice when fresh (except Catharanthus); leaves entire
                                                                           36 Pistil 1 (of 2-5 fused carpels); fruit either a 2-5-carpellate capsule or of 2 or 4 1-seeded nutlets derived from 2 carpels; plant lacking milky juice; leaves entire or serrate.
                                                                                    40 Stamens either 4, 1 fewer than the 5 corolla lobes, or 2 (with 2 staminodes); corolla usually slightly bilaterally symmetrical (the flower as a whole made bilaterally symmetrical by the 2 or 4 stamens).
                                                                         35 Corolla bilaterally symmetrical (or the corolla 2-lipped but the corolla lobes twisted so as to make the flower asymmetrical); fertile stamens fewer than the corolla lobes (except Plantago in PLANTAGINACEAE, which is equal, with 4 each; a few genera have a 5th, sterile, stamen which is obviously different in form than the 4 fertile stamens) (note that many corollas are bilabiate and the number of corolla lobes, 4 or 5, may be difficult to interpret); carpels 2.
                                                                                               45 Carpels 2, each carpel slightly to deeply lobed, separating at maturity into 4 half-carpellate units (not separating in Phyla in VERBENACEAE); fruit a schizocarp of 4 mericarps (or 2 nutlets in Phyla in VERBENACEAE).
                                                                                                 46 Inflorescence a thyrse, verticillaster, or terminal cyme, the flowers borne in cymose lateral branches; corolla strongly bilaterally symmetrical (rarely nearly radially symmetrical); stems square in ×-section (or sometimes rounded, especially on older growth); fresh plants often (but not always) aromatic
                                                                                                 46 Inflorescence of spikes, racemes, or heads, the flowers or fruits single at nodes; corolla often nearly radially symmetrical; stems rounded in X-section (rarely square); fresh plants usually not aromatic
                                                                                                                       56 Inflorescence of 1 or more terminal (and sometimes upper axillary) spikes or racemes; corolla 10-50 mm long (6-8 mm long in Phryma in PHRYMACEAE), white, pink, blue, purple, or yellow; fruit either a loculicidal capsule (OROBANCHACEAE) or a single seeded achene (Phryma in PHRYMACEAE).