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Group 6: Herbaceous angiosperms with inferior ovaries
See list of 20 families in this group-
1a. Inflorescence a capitulum (the capitula with only 1 flower in Echinops); anthers of disk flowers connate in a ring around the style; fruit a cypsela (in part)
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1b. Inflorescence not a capitulum (a capitulum-like cyme in some Caprifoliaceae); anthers not connate in a ring (except in Lobelia); fruit otherwise (except in some Caprifoliaceae)
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2a. Flowers unisexual
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3a. Plants vines, with tendrils; corolla gamopetalous [Fig. 600]
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3b. Plants not vines, without tendrils; corolla apopetalous (very inconspicuous and reduced to a rim of sepals in Hippuris)
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4a. Plants aquatic, with thin, flaccid, submersed leaves; flowers anemophilous, with an inconspicuous perianth
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5b. Leaves simple, whorled; flowers with a single stamen (in part)
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4b. Plants terrestrial, with thicker, firm leaves; flowers entomophilous, with a well-developed perianth
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6a. Leaves simple; fruit a drupe; inflorescence an axillary cymule of 3 flowers— the 2 lateral flowers usually staminate, the central bisexual (in part)
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6b. Leaves compound or evidently lobed; fruit not a drupe; inflorescence otherwise
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7a. Leaf blades 1- to 3-times pinnately compound; fruit an achene enclosed in an indurate hypanthium or a follicle (in part)
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2b. Flowers bisexual
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8b. Stems not consisting of succulent, pad-like segments, unarmed (mostly) or armed; perianth 2- to 6-merous
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9a. Leaves usually 4–6 per node, entire, with arcuate venation; flowers pseudanthial, small, collectively subtended by 4 large, white, petaloid bracts (in part)
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9b. Leaves 1–12 per node, entire, toothed, or lobed, without arcuate venation; flowers not pseudanthial, lacking petaloid bracts
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10a. Calyx 3-merous, gamosepalous, petaloid (in part)
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10b. Calyx not 3-merous (except in some Galium), connate or not, sepaloid (petaloid sepals in Aizoaceae and petaloid tepals in Comandraceae), not red-brown
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11a. Plants aquatic
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12a. Plants with a rosette of floating leaves that have petioles swollen near midlength forming a float; hypanthium with 4 stout horns, these persistent on the fruit (in part)
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12b. Plants without a conspicuous rosette of floating leaves, lacking specialized petioles with floats; hypanthium lacking horns
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13b. Leaves lacking a prominent, sheathing base; inflorescence of axillary flowers or a raceme
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14a. Leaves compound, all basal, with 3 thick, fleshy leaflets [Fig. 724]; fruit a 2-valved capsule (in part)
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14b. Leaves simple or compound, not confined to the base of a plant, not with 3 thick leaflets; fruit an achene-like drupe or a 4- or 5-valved capsule
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15a. Leaves whorled, simple; flowers with a single stamen (in part)
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15b. Leaves alternate or opposite, simple, lobed, or compound; flowers with 3, 5, or 8 stamens
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16a. Perianth 4-merous; flowers with 4 stamens; fruit a 4-valved capsule (in part)
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16b. Perianth 3- or 5-merous; flowers with 3 or 5 stamens; fruit indehiscent or a 5-valved capsule
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17b. Leaves simple and unlobed; perianth composed of 5 sepals and 5 petals; flowers with 5 antepetalous stamens
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11b. Plants of upland or wetland habitats, but typically not growing in standing water
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18b. Inflorescence not resembling a capitulum; ovary and fruit not enclosed in a tubular involucel
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19a. Gynoecium with 5–10 carpels; leaf blades conspicuously papillose, the papillae not requiring high magnification to see; fruit woody, subglobose, indehiscent, with 4–6 wings, each wing projecting into an apical horn (in part)
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19b. Gynoecium with 2–6 carpels; leaf blades without easily viewed papillae; fruit otherwise
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20a. Perianth 2- to 4-merous
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21a. Leaf blades cordate-clasping the stem [Fig. 541]; ovary mostly trilocular; fruit usually a 3-valved capsule (in part)
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21b. Leaf blades sessile or petiolate, but not clasping the stem; ovary bilocular or quadrilocular; fruit otherwise
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20b. Perianth 5-merous or absent altogether (sepals numbering 2 in the Portulacaceae; petals rarely 4 or 6 in Portulaca)
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23a. Leaves opposite; flowers with 3 or 4 stamens (5 in Triosteum) (in part)
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23b. Leaves alternate or all basal (often both alternate and opposite in Portulaca, a prostrate, fleshy-leaved herb); flowers with 5–many stamens
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24a. Inflorescence an umbel [Figs. 347,348]; fruit a schizocarp or, less commonly, a berry; leaves compound (rarely simple), usually with a sheathing petiole base; styles swollen at the base forming a stylopodium; calyx a series of small teeth around the rim of the receptacle or absent (rarely well-developed) (in part)
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24b. Inflorescence otherwise (except in Primula); fruit a capsule, pyxis, or drupe; leaves simple (trifoliate in Menyanthes), mostly without a sheathing petiole base; gynoecium without a stylopodium; calyx of evident sepals (or apparently absent in the Comandraceae)
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25a. Leaves compound, with 3 thick, fleshy leaflets; petals conspicuously pubescent on the adaxial (i.e., inner) surface [Fig. 724] (in part)
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25b. Leaves simple; petals glabrous on the adaxial surface (with a tuft of hairs near the base in Comandra)
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26a. Flowers with ca. 20 stamens; herbage pubescent with barbed hairs
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26b. Flowers with 5–10 stamens; herbage glabrous or with hairs that lack barbs
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27a. Flowers with mostly 6–10 stamens; petals yellow; prostrate weeds (in part)
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27b. Flowers with 5 stamens; petals (or tepals) white, red, green-purple, blue, or purple; plants not prostrate weeds
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28a. Perianth monochlamydeous; fruit a drupe (dryish in Comandra); leaf blades ± entire (in part)
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28b. Perianth dichlamydeous; fruit a capsule; leaf blades entire or toothed (in part)
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Each photo represents one family in this group.