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2. Osmunda Linnaeus, Sp. Pl. 2: 1063. 1753.
紫萁属 zi qi shu
Plenasium C. Presl.
Plants terrestrial, moderate-sized to large. Rhizome erect to shortly creeping, stout, woody, without scales. Fronds dimorphic or more commonly hemidimorphic with dimorphic pinnae; stipes arising as a crown at apex of rhizome, ± hairy when young, base of stipe swollen and with lateral flaplike stipules; lamina 1- or 2-pinnate, fertile portions reduced to a midrib with almost no lamina present; pinnae articulate to rachis. Sporangia large, naked, with a small patch annulus. 2n = 44.
About ten species, with some native hybrids; nearly worldwide in tropical and temperate regions, the greatest concentration of species in E and SE Asia; seven species including one putative hybrid species (one endemic) in China.
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1 |
Fronds 2-pinnate; pinnae not articulate to rachis (O. subg. Osmunda) |
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(2) |
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Fronds simple pinnate or pinnate-pinnatifid; pinnae articulate to rachis or not |
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(3) |
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2 (1) |
Fronds dimorphic or only apical portion fertile; pinnules all ?equally sized. |
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6 O. japonica |
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Fronds hemidimorphic, lower pinnae fertile; apical pinnule of each pinna much enlarged. |
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7 O. mildei |
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3 (1) |
Fronds hemidimorphic; pinnae pinnate-pinnatifid, not articulate (O. subg. Claytosmunda Yatabe, Murakami & Iwatsuki). |
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1 O. claytoniana |
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Fronds simple pinnate; pinnae entire, undulate, serrate, or roughly dentate, articulate (O. subg. Plenasium (C. Presl) C. Presl) |
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(4) |
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4 (3) |
Margin of pinnae roughly dentate. |
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2 O. banksiifolia |
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Margin of pinnae entire or serrate |
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(5) |
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5 (4) |
Fertile pinnae basal. |
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5 O. vachellii |
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Fertile pinnae medial, or above middle |
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(6) |
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6 (5) |
Margin of pinnae distinctly serrate; pinnae less than 1 cm wide. |
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3 O. angustifolia |
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Margin of pinnae entire, undulate, or minutely serrate; pinnae 1-2.5 cm wide. |
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4 O. javanica |
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Lower Taxa
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Treatments in Other Floras @ www.efloras.org
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