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Juglandaceae A. Richard ex Kunth
胡桃科 hu tao ke
Authors: Anmin Lu, Donald E. Stone & L. J. Grauke
Trees or rarely shrubs, deciduous, semievergreen, or evergreen, monoecious or rarely dioecious; bark tight (or exfoliating). Branchlets with solid or chambered pith. Terminal buds subglobose or ovoid to oblong, naked or with scales. Stipules absent. Leaves alternate (or opposite), odd- or even-pinnate, sometimes trifoliolate, rarely simple; leaflets with glandular, peltate scales, often resinous and aromatic, particularly conspicuous abaxially on young leaves and twigs, margin serrate or rarely entire. Inflorescences pendulous or sometimes erect, lateral or terminal, on reduced shoots arising on branchlets of previous year (old growth) or on current year’s growth (new growth), of several types: androgynous panicle with male, lateral spikes and female, central spike; androgynous panicle with male, mainly lateral spikes and female, central spike male at apex; cluster of male spikes and solitary female spike; or solitary male and female spikes. Flowers unisexual, anemophilous, rarely entomophilous. Male flowers subtended by an entire or 3-lobed bract; bracteoles 2 or absent; sepals 0-4, adnate to receptacle when present; stamens 3-40(-100), inserted on receptacle; filaments short to nearly absent, free or united at base; anthers glabrous or pubescent, 2-loculed, dehiscing longitudinally. Female flowers with an entire or 3-lobed bracts; bracteoles 2 or 3 (or absent); sepals 0-4, adnate to ovary, free at apex; gynoecium of 2 carpels united into an inferior ovary, 1-loculed, but at base 2-4(-8)-loculed; style 1, short or elongate, rarely absent; stigmas 2, carinal or commissural, sometimes 4-lobed, plumose or fleshy; ovule 1, orthotropous. Fruiting spike elongate, and pendulous or short and erect, rarely conelike. Fruit a drupelike nut, 2-4(-8)-chambered at base, with a dehiscent or indehiscent husk, or a 2- or 3-winged or disc-winged nutlet. Seed solitary, without endosperm. Cotyledons 4-lobed, much contorted. Germination hypogeal or epigeal. 2n = (28), 32, (64).
Nine genera and 60 or more species: mostly in temperate and subtropical regions of the N hemisphere; seven genera (one endemic) and 20 species (seven endemic, one introduced) in China.
Kuang Ko-zen & Lu An-ming. 1979. Juglandaceae. In: Kuang Ko-zen & Li Pei-chun, eds., Fl. Reipubl. Popularis Sin. 21: 6-44.
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| 1 |
Flowering spikes of both sexes erect; fruiting spike conelike, bracts persistent, overlapping; fruit a minute, 2-winged nutlet; leaves odd-pinnate |
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1 Platycarya |
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Male flowering spikes pendulous, female spike erect; fruiting spike not conelike; bracts dispersed with nuts or nutlets; fruit a small, 2- or 3-winged nutlet or a medium to large, drupelike nut with a husk; leaves odd- or even-pinnate. |
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(2) |
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| 2 (1) |
Fruiting bract 3-lobed, expanded into membranous, pinnately veined wings subtending nutlet; lateral bracteoles fused, forming a small, anterior rim or well-developed prophyll; leaves even-pinnate |
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2 Engelhardia |
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Fruiting bract entire, inconspicuous; lateral bracteoles expanded into 2 small wings on nutlet, fused into disc wing, or fused with sepals to form husk; leaves odd-pinnate. |
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(3) |
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| 3 (2) |
Branchlets with solid pith; male spikes in clusters of 3 or 5-8; drupelike nuts with a 4-9-valved, dehiscent husk. |
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(4) |
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Branchlets with chambered pith; male spikes solitary or in clusters of 3-5; disc- or 2-winged nutlets or drupelike nuts with an indehiscent or irregularly dehiscent husk. |
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(5) |
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| 4 (3) |
Leaflet margin entire; male spikes in clusters of 5-8; stamens 5-15; husk strongly keeled, splitting into 4-9 segments; nuts with attenuate apex |
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6 Annamocarya |
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Leaflet margin serrate; male spikes in clusters of 3; stamens 3-7; husk not keeled, occasionally with small flanges, splitting into 4 segments; nuts rarely with prominent, attenuate apex |
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7 Carya |
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| 5 (3) |
Fruit a large, drupelike nut, indehiscent or with an irregularly dehiscent husk; germination hypogeal; female spike usually less than 10-flowered, erect |
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5 Juglans |
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Fruit a small, winged nutlet, indehiscent; germination epigeal; female spike 10- to numerous flowered, pendulous. |
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(6) |
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| 6 (5) |
Fruit a disc-winged nutlet; male spikes in clusters of 3-5 |
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3 Cyclocarya |
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Fruit a 2-winged nutlet; male spike solitary |
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4 Pterocarya |
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Lower Taxa
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