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13. Commelina Linnaeus, Sp. Pl. 1: 40. 1753; Gen. Pl. ed.; 5:25, 1754.
鸭跖草属 ya zhi cao shu
Herbs annual or perennial. Rhizomes absent. Stems creeping, ascending, or erect. Leaves alternate. Cincinni subtended by and included in spathelike involucral bracts; involucral bracts open or proximal margins coherent and becoming funnelform, often forming heads; cincinni dichotomously branched, flowers in 1 branch smaller, infertile, falling early, those in other branch fertile; bracts not falcate curved, usually extremely small or absent. Flowers zygomorphic. Sepals lanceolate or ovate-orbicular, sometimes shallowly boat-shaped, inner 2 often connate at base. Petals free, blue, spatulate or orbicular, inner (anterior) 2 larger and clawed. Fertile stamens 3, on 1 side, 2 inserted opposite sepals, 1 opposite petal; filaments glabrous; staminodes 3; antherodes 4-lobed, butterflylike. Ovary 2- or 3-loculed, posterior locule with 1 developed or abortive ovule or empty, anterior 2 locules each with 1 or 2 ovules. Capsule oblong, globose, or ellipsoid, 3- or most frequently 2-valved; posterior valve 1-seeded or seedless, often indehiscent; anterior 2 valves each seedless or 1- or 2-seeded. Seeds cylindric or ellipsoid, reticulate or subsmooth; hilum linear.
About 170 species: mainly in tropical and subtropical regions; eight species in China.
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| 1 |
Proximal margin of involucral bracts open or folded but not basally connate, base cordate or rounded. |
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(2) |
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Proximal margin of involucral bracts connate, becoming funnelform. |
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(4) |
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| 2 (1) |
Capsule 3-valved; spathelike involucral bracts lanceolate, base cordate or rounded |
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1 Commelina diffusa |
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Capsule 2-valved; spathelike involucral bracts cordate. |
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(3) |
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| 3 (2) |
Leaf blade 8--13 × 3--5 cm; valves 1-seeded; spathe obtuse at apex |
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3 Commelina suffruticosa |
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Leaf blade 3--9 × 1.5--2 cm; valves 2-seeded; spathe acute at apex |
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2 Commelina communis |
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| 4 (1) |
Capsule 3-valved; seeds 2 per valve; leaves obviously petiolate, leaf blade ovate to broadly ovate, less than 7 cm |
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4 Commelina benghalensis |
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Capsule 2- or 3-valved; seeds 1 per valve; leaves sessile (or petiolate and involucral bracts very small), leaf blade lanceolate to ovate-lanceolate, to 15 cm. |
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(5) |
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| 5 (4) |
Spathelike involucral bracts ca. 1 cm; plants often glabrous; leaves 2--4(--6) cm |
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8 Commelina auriculata |
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Spathelike involucral bracts ca. 2 cm or more; plants hairy, less often glabrous; leaves more than 6 cm. |
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(6) |
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| 6 (5) |
Plants robust, to 1 m tall; leaves 7--20 × 2--7 cm, leaf sheath mouth densely brown hirsute-ciliate; spathelike involucral bracts 4--10 |
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5 Commelina paludosa |
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Plants slender, short; leaves less than 12 × 2.5 cm, leaf sheath mouth glabrous or sparsely whitish hispid-ciliate; spathelike involucral bracts 1 to several. |
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(7) |
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| 7 (6) |
Plants usually creeping and branched; leaf blade ovate-lanceolate; spathelike involucral bracts 2 or 3, ca. 2 cm, apex acute; capsule 3-valved |
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6 Commelina maculata |
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Plants erect or ascending, less often creeping and branched; leaf blade lanceolate, apex acuminate; spathelike involucral bracts 1 to several, ca. 2.5 cm, apex shortly falcate-acuminate; capsule 2-valved, posterior valve falling with enclosed seed |
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7 Commelina undulata |
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Lower Taxa
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