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Group 10: Herbaceous angiosperms with superior ovaries, actinomorphic flowers, distinct petals or the petals lacking, and 2 or more connate carpels
See list of 43 families in this group-
1a. Plants submerged aquatics, attaching to the substrate by fleshy disks; flowers without perianth, borne singly in the axils of leaves, subtended by a tubular spathe
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1b. Plants aquatic or terrestrial, but not attaching to the substrate by fleshy disks; flowers with at least 1 whorl of perianth (sometimes so in only 1 sex of flower; lacking perianth in Callitriche, Euphorbia, and Saururus), borne variously, not subtended by a tubular spathe
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2a. Inflorescence a cylindrical, usually nodding spike produced on a peduncle opposite the leaves with 175–300 flowers that lack perianth and have 3–5 (usually 4) carpels that are basally connate and mature as rugose mericarps (in part)
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2b. Inflorescence not combinging the above characteristics, usually of a different type (e.g., cyme, raceme), with fewer flowers, and/or with perianth
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3a. Placentation laminar; plants aquatic, with conspicuous elliptic or orbicular floating leaf blades with 2 basal lobes [Fig. 55], arising directly from a rhizome (in part)
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3b. Placentation otherwise; plants terrestrial or aquatic; leaf blades various, but not at once floating, basally lobed, and arising from an underwater rhizome
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4a. Inflorescence a cyathium, with a single carpellate flower and 2 or more staminate flowers borne in a cupuliform involucre, the margin of the involucre sometimes subtended by petaloid glands, the entire arrangement resembling a single flower; plants often with milky latex (in part)
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4b. Inflorescence not pseudanthial; plants with watery sap (milky or colored latex in the Papaveraceae)
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5a. Calyx of 2, often caducous, sepals; petals wrinkled in bud; plants with milky or colored latex (in part)
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5b. Calyx of 3 or more sepals (2 sepals in the Portulacaceae and some Elatinaceae), or the perianth monochlamydeous and with 3 or more tepals, or the perianth absent; petals arranged otherwise in bud (wrinkled in the Lythraceae); plants with watery sap
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6a. Plants insectivorous by means of viscid hairs or pitcher-shaped leaves [Figs. 604,902], of organic soils; leaves all basal
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7a. Leaf blades with viscid, glandular-hairs, flat, the margins not connate; inflorescence a raceme; styles 3, distinct
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7b. Leaf blades without glandular hairs, the margins connate, thereby forming a tube that is retrorsely pubescent on the adaxial (i.e., inside) surface [Fig. 902]; inflorescence a single flower; styles 5, connate, modified into a 5-rayed, umbrella-shaped body
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6b. Plants not insectivorous, of mineral or organic soils; leaves variously arranged
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8a. Leaves opposite or whorled (sometimes the upper alternate in Chrysosplenium) [Figs. 628,685,768]
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9a. Leaves parapinnate, 1 of each node conspicuously larger than the other; fruit a schizocarp, each mericarp with 2 divergent horns and a central row of tubercles and transversely divided into 3–5 1-seeded compartments
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9b. Leaves simple, lobed, or compound, when pinnately compound then imparapinnate, those of a given node ± equal in size; fruit an achene, berry, pyxis, silique, silicle, capsule, or a schizocarp but then lacking horns and tubercles and not transversely divided into compartments
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10a. Plants free-floating, rootless, aquatic; leaves 2- to 4-times dichotomously forked [Fig. 51]; perianth composed of 7–15 basally connate sepals; fruit an achene with 2–15 marginal spines
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10b. Plants usually rooted, terrestrial or aquatic; leaves not dichotomously forked; perianth otherwise (consisting of up to 10 basally connate sepals in some Euphorbiaceae); fruit various, but not an achene with marginal spines
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11a. Basal leaves peltate, 30–40 cm wide; fruit a yellow berry 40–50 mm wide (in part)
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11b. None of the leaves peltate, narrower; fruit an achene, capsule, pyxis, silique, or schizocarp
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12a. Leaf blades punctate with pellucid dots, sessile; petals yellow or flesh-colored to pink (in part)
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12b. Leaf blades not pellucid-punctate, sessile or petiolate; petals variously colored, usually not yellow or flesh-colored (yellow in 1 species of Portulaca and some Linum) or absent
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13a. Leaf blades scale-like and sessile; flowers sunken into the fleshy, jointed stem [Fig. 340]; plants coastal halophytes (in part)
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13b. Leaf blades foliaceous (though they may be small), sessile or petiolate; flowers not sunken into a fleshy, jointed stem; plants of various habitats
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14a. Plants aquatic (though sometimes stranded after water level decline); androecium with 1–3 stamens
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15a. Leaves crowded at the apex forming a floating rosette (not forming a rosette in 2 species) [Fig. 766]; flowers unisexual, without perianth; fruit a schizocarp (in part)
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15b. Leaves not crowded at the apex; flowers bisexual, with sepals and petals; fruit an achene
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14b. Plants terrestrial or of wetland habitats; androecium with 4–10 stamens
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16a. Perianth monochlamydeous
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17a. Perianth petaloid
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18a. Leaves whorled, 3–8 per node; placentation axile (in part)
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18b. Leaves opposite; placentation basal or free-central (axile in Sesuvium)
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19a. Sepals with subterminal, slender, horn-like appendages; fruit a pyxis (in part)
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19b. Sepals lacking subterminal appendages; fruit an achene or capsule
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20a. Flowers in a cyme, with a sepaloid involucre subtending 1–5 flowers and a petaloid calyx [Fig. 732]; fruit an achene, enclosed in an indurate calyx (collectively called an anthocarp); cultivated and escaped plants
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20b. Flowers axillary, with only a petaloid calyx; fruit a 5-valved capsule; native plants of coastal saltmarshes (in part)
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17b. Perianth sepaloid or inconspicuous
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21a. Flowers with 7–20 or more stamens; style branches bifid or laciniately divided; fruit a capsule-like schizocarp with 2 or 3 mericarps (in part)
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21b. Flowers with 1–8 stamens; style branches simple (though the stigmatic surface may be fringed in some fashion); fruit a 2- to 10-valved capsule or utricle
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22a. Stamens 4–8, set in the notches of an 8-lobed disk that fills much of the center of the flower; fruit a 2-valved capsule (in part)
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22b. Stamens 1–5, not set on a disk; fruit an achene or a 3- to 10-valved capsule
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23a. Flowers unisexual; fruit an achene
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24a. Ovary with 2 styles; leaf blades palmately lobed or divided; staminate flowers each with 5 stamens (in part)
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24b. Ovary with 1 style; leaf blades simple, without lobes or divisions; staminate flowers each with 4 stamens or 5 in Laportea (in part)
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23b. Flowers bisexual; fruit a capsule (a utricle in Scleranthus)
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25a. Ovary with 3–5 locules; placentation axile; leaves whorled (in part)
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25b. Ovary with a single locule; placentation free-central; leaves opposite (in part)
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16b. Perianth dichlamydeous
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26a. Calyx of 2 sepals [Fig. 805]; stamens antepetalous (in part)
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28a. Leaf blades palmately lobed or palmately divided; androecium composed of 6 tetradynamous stamens; fruit a silique or silicle (in part)
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28b. Leaf blades simple; androecium composed of 4 or 8 stamens; fruit a capsule
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29a. Anthers dehiscing by a single, terminal pore; filaments twisted, thereby bringing all the stamens to 1 side of the flower at anthesis; leaf blades 20–70 mm long
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29b. Anthers dehiscing by longitudinal slits; filaments not twisted to 1 side; leaf blades 2–23 (–30) mm long
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30a. Sepals (1–) 1.5–3 mm long, entire at the apex; leaf blades linear-subulate; capsules 2–4 mm long (in part)
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30b. Sepals 0.7– 1 mm long, 3-cleft at the apex; leaf blades ovate to oblong; capsules 0.6–0.9 mm long (in part)
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31a. Anthers dehiscing by 2 terminal pores; stigmas large, peltate, orbicular, with 4 or 5 lobes (in part)
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31b. Anthers dehiscing by longitudinal slits; stigmas smaller, linear to capitate, without lobes
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32a. Style branches bifid or laciniately divided [Fig. 625]; fruit a capsule-like schizocarp with 3 mericarps (in part)
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32b. Style branches simple (though the stigmatic surface may be fringed in some fashion); fruit a 2- to 10-valved capsule or a schizocarp separating into 5 mericarps
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33a. Leaf blades palmately lobed or pinnately divided; fruit a schizocarp, with 5 1-seeded mericarps that elastically dehisce from a persistent, central column [Fig. 672]
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33b. Leaf blades simple and unlobed; fruit a capsule
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34a. Flowers perigynous, with intersepalar appendages; ovary 2-locular (in part)
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34b. Flowers hypogynous (perigynous in Scleranthus), without intersepalar appendages; ovary 1- or 10-locular
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35a. Capsule with 10 locules; placentation apical-axile; stamens alternating with small staminodes in some species; calyx aposepalous (in part)
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35b. Capsule with a single locule; placentation free-central; androecium without staminodes; calyx apo- or gamosepalous
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36a. Androecium with 6 stamens in 2 whorls, the outer whorl shorter than the inner; flowers sessile; placentation parietal
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36b. Androecium with 1–10 stamens in 1 or 2 whorls, when in 2 whorls the stamens not dissimilar as to length; flowers pedicellate (sessile in Herniaria and Scleranthus); placentation free-cental (in part)
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37a. Leaf blades compound, trifoliate, with obcordate leaflets [Fig. 756]; petals white with pink stripes or yellow
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37b. Leaf blades simple to compound, but not as above; petals variously colored or absent
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38a. Flowers with 4 petals (very rarely 0 or 2); androecium with 6 stamens arranged in tetradynamous fashion (rarely only 2 stamens, numbering 6 but not tretradynamous in Cleome); fruit a silique or silicle
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39b. Flowers subtended by bracts; stamens 6, all elongate; silique unilocular (in part)
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38b. Flower with 0–6 petals; androecium with a variable number of stamens, but never 6 and tetradynamous; fruit otherwise
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40a. Stamens monadelphous, the filaments forming a conspicuous tube surrounding the style [Fig. 720]; gynoecium composed of 5–40 carpels (in part)
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40b. Stamens distinct or connate at only the very base; gynoecium composed of 1–6 (–7) carpels
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41a. Leaves with tubular, sheathing stipules (i.e., ocreae); flowers subtended by tubular, sheathing bracteoles (i.e., ocreolae) (in part)
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41b. Leaves without tubular, sheathing stipules; flowers not subtended by tubular, sheathing bracteoles
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42a. Leaf blades compound
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43a. Perianth 3-merous, the sepals not petaloid; flowers solitary on thin peduncles from the axils of leaves; fruit a schizocarp
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43b. Perianth (3–) 4- to 6-merous, the sepals petaloid; flowers borne in cymes or racemes, or borne singly at the summit of the stem or tips of branches, or singly on scapes; fruit a blue seed or an achene, berry, follicle, or capsule
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44a. Anthers dehiscing by flaps; stamens as many as the petals and opposite them (i.e., antepetalous); fruit an exposed, blue seed or a capsule (in part)
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44b. Anthers dehiscing by longitudinal slits; stamens numbering more than the petals; fruit an achene, berry, or follicle
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45a. Leaf blades 2- or 3-times divided or dissected into numerous, very narrow segments; fruit a follicle or berry; sepals caducous or not (in part)
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45b. Leaf blades 1-time divided ; fruit an achene enclosed in an indurate hypanthium or a follicle; sepals not caducous (in part)
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42b. Leaf blades simple, toothed, or lobed but not divided
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46a. Perianth sepaloid
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47a. Stamens 10 per flower; fruit a 5- to 7-lobed and locular capsule [Fig. 762]
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47b. Stamens 1–5 per flower (as many as 20 or more in some Euphorbiaceae); fruit an achene, utricle, pyxis, berry, multiple, or 3-locular capsule or capsule-like schizocarp
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48a. Flowers perigynous, bisexual; leaf blades palmately lobed (in part)
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48b. Flowers hypogynous, unisexual or sometimes bisexual in the Amaranthaceae; leaf blades simple to pinnately lobed (palmately lobed in Ricinus, which has a peltate attachment of the petiole)
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49a. Filaments stout, nearly as wide as the anthers, white, primarily responsible for the flower color; leaf blades thick and evergreen
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49b. Filaments more slender, not as wide as the anthers, not imparting an evident white color to flowers; leaf blades thinner and deciduous
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50a. Ovary 3-locular (1-locular in Crotonopsis); styles 2 or 3, each 1 bifid [Fig. 625]; fruit a capsule-like schizocarp with 2 or 3 mericarps (an achene in Crotonopsis) (in part)
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50b. Ovary 1-locular; styles 1–3, without additional branching (though the stigmatic surface may be fringed in some fashion); fruit an achene, utricle, multiple, or pyxis
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51a. Sepals usually dry and scarious; filaments distinct or, more commonly, connate at least near the base; ovary with 3 stigmas (in part)
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51b. Sepals membranaceous to herbaceous (hyaline in Axyris); filaments distinct; ovary with usually 1 or 2 stigmas
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52a. Proximal portion of first pair of primary lateral veins at the very margin of the leaf blade (i.e., the basiscopic side of the vein exposed for a short distance); stems with minute, uncinate hairs; fruit a multiple of achenes (in part)
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52b. First pair of primary lateral veins not at the margin of the leaf blade (i.e., both the basiscopic and acroscopic sides bordered by green leaf tissue) or the leaf blades with 1 nerve and lateral veins lacking; stems variously glabrous to pubescent, but lacking uncinate hairs; fruit an achene, utricle, or pyxis
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53a. Ovary with 1 stigma; flowers unisexual; plants sometimes with stinging hairs (in part)
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53b. Ovary with 2 (–5) stigmas; flowers unisexual or bisexual; plants without stinging hairs (in part)
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46b. Perianth, at least in part, petaloid (though caducous in Hydrastis)
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54a. Plants lacking chlorophyll, the stems white to pink, yellow to brown, or pink to red; leaves reduced and scale-like [Fig. 616] (in part)
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54b. Plants with chlorophyll, the stems and/or leaves green; leaves foliaceous
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55a. Anthers dehiscing by 2 apical pores; leaves all basal; fruit a 5-valved capsule (in part)
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55b. Anthers dehiscing by longitudinal slits; leaves and fruits various
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56a. Gynoecium with 5–12 (–15) styles; fruit a berry
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57a. Flowers with 5 sepals and consistently with 10 styles, arranged in a raceme; berry dark purple; leaf blades unlobed
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57b. Flowers with 3 caducous sepals and with a variable number of styles, solitary at the summit of the stem; berry red; leaf blades palmately lobed (in part)
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56b. Gynoecium with 2–7 styles; fruit a capsule, pyxis, or utricle
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58a. Flowers perigynous
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59a. Perianth 6-merous; sepals alternating with appendages at the rim of the hypanthium; petals crumpled in bud (in part)
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59b. Perianth 5-merous; sepals not alternating with appendages; petals mostly imbricate in bud, not crumpled
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60a. Androecium with 5 stamens and 5 trifid, white staminodes; petals 10–18 mm long; flowers with 4 carpels; fruit a 4-locular capsule (in part)
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60b. Androecium with 10 stamens; petals 2–6 mm long; flowers with 2 carpels; fruit a follicle or a 1- or 2-locular capsule (in part)
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58b. Flowers hypogynous
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61a. Calyx definitely gamosepalous; halophytic plants of Atlantic coast shores
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61b. Calyx aposepalous or nearly so, connate at only the very base, if at all; plants not halophytic
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62a. Calyx composed of 2 sepals; stems prostrate; fruit a pyxis (in part)
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62b. Calyx composed of 5 sepals; stems upright; fruit a capsule
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63a. Gynoecium of 5 carpels; capsule 10-valved; leaves borne on a stem (in part)
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63b. Gynoecium of 2 or 4 carpels; capsule 2- or 4-valved; leaves all basal or essentially so
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64a. Androecium with 5 stamens and 5 trifid, white staminodes; petals 10–18 mm long; flowers with 4 carpels; fruit a 4-locular capsule (in part)
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64b. Androecium with 10 stamens; petals 2–6 mm long; flowers with 2 carpels; fruit a follicle or a 1- or 2-locular capsule (in part)
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