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19. Gossypium Linnaeus, Sp. Pl. 2: 693. 1753.
棉属 mian shu
Herbs annual or perennial, sometimes shrubs; all parts irregularly dotted with dark oil glands. Leaf blades usually palmately 3-9-lobed, rarely entire. Flowers solitary, subterminal. Pedicel not articulated, usually with glands below insertion of epicalyx lobes. Epicalyx lobes 3(-7), foliaceous, glandular, free or connate at base, entire or toothed to deeply laciniate. Calyx cup-shaped, nearly truncate to 5-lobed. Corolla white or yellow, sometimes with purple center, large; petals 5, apex rounded. Staminal column with many anthers along entire length, apex truncate. Ovary 3-5-loculed; ovules 2 to many per locule; style short, rod-shaped, stigma clavate, 5-grooved. Capsule globose or ellipsoid, loculicidally dehiscent. Seeds globose, densely white long woolly, mixed with short hairs or without short hairs.
About 20 species: tropical and subtropical regions; four species (all introduced) in China.
No wild species of Gossypium have been recorded from China. The genus is economically very important as the source of cotton and cotton seed oil, and all the taxa recorded from China have been very widely cultivated throughout tropical and warm temperate regions. Many taxa of cultivated cotton have been described, some from Chinese material, but these are all now included within the four species recognized below.
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| 1 |
Epicalyx lobes connate at base, entire or 3-7-toothed, teeth 1-2 × as long as wide or wider than long; calyx shallowly cup-shaped, entire or nearly truncate, rarely lobed; filaments ± equal in length |
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(2) |
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Epicalyx lobes free at base, toothed, teeth 3-4 × as long as wide; calyx 5-toothed, sometimes lobed or truncate; filaments unequal in length, the upper ones longer |
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(3) |
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| 2 (1) |
Leaf blade palmately 3-5-lobed; epicalyx lobes longer than wide, entire or 3-4-toothed near apex; capsule conical, apex tapering. |
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1 G. arboreum |
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Leaf blade palmately (3 or)5(or 7)-lobed; epicalyx lobes wider than long, 6-8-toothed near apex; capsule ovoid, apex beaked. |
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2 G. herbaceum |
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| 3 (1) |
Leaf blade lobes broadly triangular to ovate-orbicular; epicalyx lobes 3, margin 7-9-toothed near apex; staminal column 1-2 cm, filaments spreading; capsule ovoid; seeds with long wool and persistent short wool. |
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3 G. hirsutum |
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Leaf blade lobes ovate to oblong; epicalyx lobes 5 or more, margin 10-15-toothed; staminal column 3.5-4 cm, filaments erect; capsule oblong-ovoid; seeds with long wool and easily detached short wool. |
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4 G. barbadense |
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Lower Taxa
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