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4. Pterocarya Kunth, Ann. Sci. Nat. (Paris). 2: 345. 1824.
枫杨属 feng yang shu
Trees deciduous, monoecious. Branchlets with chambered pith. Terminal buds oblong, naked, or with 2-4 overlapping scales. Leaves odd- or even-pinnate; leaflets 5-21(-25), margin serrate. Inflorescences lateral or terminal on old or new growth, pendulous; male and female inflorescences separate: male spike solitary, lateral on old growth or at base of new growth; female spike terminal on new growth. Male flowers with an entire bract; bracteoles 2; sepals 4; stamens 5-18, anthers glabrous or pubescent. Female flowers with a small, entire bract, adnate to ovary but nearly free at base; bracteoles 2, adnate to ovary but nearly free above bract on posterior side; sepals 4, adnate to ovary, free at apex; style short; stigmas carinal, 2-lobed, plumose. Fruiting spike elongate, pendulous. Fruit a 2-winged nutlet, 4-chambered at base. Germination epigeal.
Six species: E and SW Asia; five species (two endemic) in China.
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1 |
Terminal buds with 2-4 caducous scales; branchlets with narrow bands of bud-scale scars; male spike lateral at base of new growth; bract of female flowers ca. 3 mm, densely tomentose; nutlets without lacunae in wall. |
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(2) |
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Terminal buds naked; branchlets without bud-scale scars; male spike lateral on old growth or scattered on new growth; bracts of female flowers less than 2 mm, glabrous or puberulent; nutlets with large lacunae in wall. |
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(3) |
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2 (1) |
Leaflets 11-21; axis of fruiting spike pubescent; nutlets glabrous, wings semiorbicular, 1.3-2.1 × 0.9-1.8 cm |
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4 Pterocarya rhoifolia |
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Leaflets 7-13; axis of fruiting spike glabrous or pubescent; nutlets glabrous or pubescent, wings orbicular-ovate to elliptic-rhomboid, 1-3 × 1-2 cm |
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5 Pterocarya macroptera |
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3 (1) |
Leaflets 5-11(-15); rachis wingless; nutlet wings broad, elliptic-ovate |
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1 Pterocarya hupehensis |
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Leaflets usually 6-21(-25); rachis winged or not; nutlet wings narrow, linear or oblong-linear. |
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(4) |
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4 (3) |
Rachis usually winged, at least in part; leaflets elliptic or elliptic-lanceolate, 6-12 × 2-3 cm, apex obtuse to acute |
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2 Pterocarya stenoptera |
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Rachis wingless; leaflets ovate or elliptic-ovate, 9-17 × 3-7 cm, apex acute to acuminate |
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3 Pterocarya tonkinensis |
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Lower Taxa
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