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HAMAMELIDACEAE R. Brown
金缕梅科 jin lu mei ke
Authors: Zhi-Yun Zhang, Hongda Zhang & Peter K. Endress
Shrubs or trees, evergreen or deciduous, hermaphroditic, andromonoecious, or monoecious. Indumentum usually of stellate hairs or stellate or peltate scales. Buds perulate or naked. Leaves distichous or spiral, rarely subopposite or opposite, stipules minute to large, usually paired (solitary and enclosing bud in Mytilaria, and apparently absent in Rhodoleia); petiole usually well defined; leaf blade simple or palmately lobed, pinnately veined or palmately 3–5-veined. Inflorescences usually spikes or heads, rarely racemes or (condensed) thyrses or panicles, axillary or terminal. Flowers small to medium-sized, bracteate and often bracteolate, bisexual or unisexual, actinomorphic or rarely zygomorphic (Rhodoleia), hypogynous to epigynous, floral cup shallow to urn-shaped, sometimes absent; sepals 4 or 5(–10), sometimes absent, imbricate, usually persistent; petals absent or 4 or 5, yellow, white, greenish or red, often ribbonlike and circinate in bud, caducous; stamens 4, 5, or many, free, rarely arranged in 2 whorls with the inner whorl staminodal, development of polyandrous androecia centripetal or centrifugal; anthers basifixed, thecae mostly bisporangiate, each opening by two valves or a simple longitudinal slit, or monosporangiate and opening by a single valve (Exbucklandia, Hamamelis and the genera of the S hemisphere), connective protruding; disk scales sometimes present between stamens and carpels. Ovary 2-locular, carpels free at apex; ovules mostly 1 per carpel, less often many, but then most of them sterile, crassinucellar, bitegmic, anatropous, halfway between apotropous and epitropous, pendent from ovary top if solitary, along the carpellary margins if numerous; placentation axile. Styles and stigmas 2. Fruit a capsule, dehiscing septicidally, septifragally, or loculicidally and 4-valved; endocarp woody or leathery, usually loose from leathery exocarp. Seeds 1 to many per carpel; if solitary then seed coat thick, hard, smooth and shiny, black or brown; if numerous then sometimes winged and only a few viable. Endosperm thin; embryo straight; cotyledons leaflike, radicle short.
About 30 genera and 140 species: E and S Africa (including Madagascar), E, W, and SE Asia, NE Australia, Central, North, and South America, Pacific Islands; 18 genera (four endemic) and 74 species (58 endemic) in China.
Several genera and species need critical revision.
Chang Hung-ta. 1979. Hamamelidaceae. In: Chang Hung-ta, ed., Fl. Reipubl. Popularis Sin. 35(2): 36–116.
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| 1 |
Ovules and seeds several to many per carpel; inflorescences capitate or spicate; leaves palmately veined, sometimes lobed (pinnately veined in Rhodoleia and Altingia). |
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(2) |
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Ovules and seeds 1(–3) in each carpel (Corylopsis with 2 extra, abortive ovules in each carpel); inflorescences racemose, spicate or condensed thyrses or panicles; leaves pinnately veined, undivided. |
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(9) |
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| 2 (1) |
Stipules apparently absent; leaves pinnately veined, entire; petals spatulate to oblanceolate, red; inflorescence axillary, nodding, enclosed by conspicuous involucre of rounded bracts as long as flowers. |
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6 Rhodoleia |
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Stipules present; leaves usually palmately veined, often acuminately lobed (pinnately veined and simple in Altingia); petals linear or absent; inflorescence terminal, not nodding, not enclosed by involucre. |
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(3) |
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| 3 (2) |
Stipules large, leaving each node with prominent annular scar; infructescences elongate or, if ± capitate, capsules clearly exserted. |
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(4) |
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Stipules linear, leaving small discrete scars; infructescences globose, capsules not or only slightly exserted, or inflorescence 2-flowered. |
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(6) |
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| 4 (3) |
Inflorescence capitate; anthers 2-locular. |
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5 Exbucklandia |
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Inflorescence spicate; anthers 4-locular. |
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(5) |
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| 5 (4) |
Stipule 1, long and tubular; petals present. |
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7 Mytilaria |
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Stipules 2, rounded; petals absent. |
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8 Chunia |
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| 6 (3) |
Inflorescence with 2 opposite flowers; flower with 5 stamens; petals red. |
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1 Disanthus |
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Inflorescence with 5 or more flowers; flowers with more than 5 stamens; petals white or absent. |
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(7) |
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| 7 (6) |
Styles and staminodes caducous; leaves undivided, pinnately veined. |
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2 Altingia |
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Styles and staminodes persistent; leaves lobed, or at least basally 3-veined. |
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(8) |
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| 8 (7) |
Leaf blade palmately 3–5-lobed, base cordate; infructescence globose. |
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3 Liquidambar |
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Leaf blade heteromorphic, undivided and basally 3-veined or palmately 3-lobed, base cuneate; infructescence semiglobose with truncate base. |
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4 Semiliquidambar |
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| 9 (1) |
Petals absent, stamens variable in number. |
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(10) |
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Petals and stamens usually 4 or 5, rarely petals reduced. |
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(13) |
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| 10 (9) |
Inflorescences capitate spikes, without terminal flowers, each flower with simple bract and without bracteoles, sepals present; capsules arranged spirally along main axis, sessile. |
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(11) |
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Inflorescences condensed panicles or botryoids with terminal flowers, each flower with (often 3-parted) bract and (none or)1 or 2 (3-parted or simple) bracteoles, sepals absent; capsules arranged mostly distichously along main axis, sometimes stalked. |
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(12) |
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| 11 (10) |
Leaves evergreen, venation brochidodromous. |
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9 Sycopsis |
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Leaves deciduous, venation craspedodromous. |
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10 Parrotia |
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| 12 (10) |
Floral cup absent. |
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11 Distylium |
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Floral cup present. |
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12 Distyliopsis |
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| 13 (9) |
Petals long, linear, circinate; inflorescences shortly spicate. |
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(14) |
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Petals obovate or reduced and scalelike, 5-merous; inflorescences racemose or spicate, elongated. |
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(15) |
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| 14 (13) |
Anthers with 2 pollen sacs, dehiscing with 2 valves; flowers 4-merous; leaf margin serrate. |
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13 Hamamelis |
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Anthers with 4 pollen sacs, dehiscing with 4 valves; flowers usually 4–5(–6)-merous; leaf margin entire to sparsely serrulate. |
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14 Loropetalum |
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| 15 (13) |
Stigma large, conspicuously expanded; styles long. |
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15 Eustigma |
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Stigma not expanded; styles mostly short. |
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(16) |
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| 16 (15) |
Flowers bisexual; petals well-developed, spatulate, staminodes often also present, floral cup 1/2 as long as capsule; capsules subsessile. |
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16 Corylopsis |
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Flowers mostly unisexual (bisexual flowers may also occur); petals scalelike or very reduced to absent, staminodes absent in male flowers; floral cup obconical with ovary exserted or urceolate and enclosing ovary. |
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(17) |
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| 17 (16) |
Flowers pedicellate; petals scalelike, ovary semi-inferior; floral cup obconical, ovary exserted; fruit usually conspicuously lenticellate. |
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17 Fortunearia |
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Flowers sessile; petals lacking or present as tiny rudiments; ovary nearly superior; floral cup urceolate, distinctly narrowed at mouth and concealing ovary; fruit not lenticellate. |
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18 Sinowilsonia |
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List of lower taxa
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