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1. Zostera Linnaeus, Sp. Pl. 2: 968. 1753.
大叶藻属 da ye zao shu
Rhizome monopodial, with 2 vascular bundles in cortex. Shoots short, with several leaves; flowering stems usually elongated, with several spathes. Leaves linear, with 3-11 parallel veins, margin entire or rarely minutely denticulate; sheaths membranous or subleathery, with an auricle, ligulate. Spadix axillary, sessile, axis flattened, without or only with inconspicuous projections (retinacula). Plants monoecious; flowers unisexual, small. Anthers 2-celled. Style short; stigmas 2, filiform or subulate. Fruit ovoid, with a short beak.
About 12 species: best represented along shores of N temperate regions; five species in China.
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| 1 |
Leaves 3-veined; sheaths open; projections present on each side of spadix axil. |
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5 Z. japonica |
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Leaves 5-11-veined; sheaths closed; projections usually absent |
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(2) |
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| 2 (1) |
Rhizomes slightly erect, with very short internodes; sheaths slightly leathery, persistent; leaf apex retuse. |
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2 Z. caespitosa |
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Rhizomes creeping, internodes elongated; sheaths usually membranous, not persistent; leaf apex obtuse or mucronate, rarely retuse |
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(3) |
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| 3 (2) |
Seeds longitudinally ribbed; leaves 5-7-veined. |
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1 Z. marina |
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Seeds smooth on surface; leaves 5-11-veined |
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(4) |
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| 4 (3) |
Leaves 5-8 mm wide, apex obtuse or mucronate; fruit ca. 4 mm. |
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3 Z. caulescens |
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Leaves 1-1.5 cm wide, apex truncate or retuse; fruit 5-6.5 mm. |
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4 Z. asiatica |
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Lower Taxa
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