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2. Tamarix Linnaeus, Sp. Pl. 1: 270. 1753.
柽柳属 cheng liu shu
Shrubs or trees, much branched. Young branches usually glabrous; two types of branches present: ligneous growing branches, not deciduous in winter vs. green vegetative branchlets, deciduous in winter. Leaves alternate, sessile, amplexicaul or vaginate, small, scale-like, glabrous, rarely hairy, mostly with salt-secreting glands. Flowers in racemes or panicles, blooming in spring; racemes lateral on growing branches of previous or current year and clustered in terminal panicles, or two types of flowering habits present in some species. Flowers bisexual, rarely unisexual, 4- or 5(or 6)-merous, usually pedicellate; bract 1. Calyx herbaceous or fleshy, 4- or 5-fid; lobes entire or faintly denticulate. Petals as many as calyx lobes, deciduous or persistent after anthesis. Disk variously shaped, mostly 4- or 5-lobed; lobes entire, or apex retuse or even deeply divided. Stamens 4 or 5, opposite to calyx lobes, or numerous, outer series opposite to calyx lobes; filaments often free, inserted between lobes of disk or at apices of lobes; anthers cordate, versatile, 2-thecate, longitudinally dehiscent. Pistil consisting of 3 or 4 carpels; ovary mostly conic, many seeded; placentation basal-parietal; styles 3 or 4; stigmas capitate, short. Capsule conic, abaxially 3-septicidal. Seeds numerous, minute; apical awns villous.
About 90 species: Africa, Asia, Europe; 18 species (seven endemic) in China.
Tamarix tenuissma Nakai (J. Jap. Bot. 14: 292. 1938), described from Japan and Korea, was recorded from Liaoning (Dalian) and said to have ten stamens, but the Tamarix plants known in this region all have five stamens, so the identity of the record cannot yet be determined. Further study is required.
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| 1 |
Leaves reduced, totally amplexicaul and vaginate on branches of current year |
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(2) |
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Leaves not amplexicaul, nor vaginate |
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(4) |
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| 2 (1) |
Filaments between disk lobes; flowers usually blooming in summer and autumn, rarely in spring. |
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16 T. aphylla |
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Filaments at apex of disk lobes; flowers blooming only in summer and autumn |
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(3) |
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| 3 (2) |
Leaves (nearly all) amplexicaul and vaginate; flowers 4-4.5(-7) mm in diam.; petals deciduous after anthesis; racemes 5-7(-15) cm. |
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17 T. taklamakanensis |
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Leaves amplexicaul and vaginate, but sheaths not totally closed; flowers less than 4 mm in diam.; petals persistent after anthesis; racemes 2-5(-8) cm. |
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18 T. sachensis |
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| 4 (1) |
Racemes in spring lateral on growing branches of previous year; flowers 4- or 5-merous |
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(5) |
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Racemes on branches of current year, forming a panicle; flowers all 5-merous; flowers blooming in summer and autumn |
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(12) |
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| 5 (4) |
Flowers 4-merous |
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(6) |
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Flowers 5-merous |
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(9) |
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| 6 (5) |
Racemes 6-15(-25) cm. |
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1 T. elongata |
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Racemes usually 4-6(-7) cm |
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(7) |
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| 7 (6) |
Bracts less than 1/2 as long as pedicels. |
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2 T. laxa |
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Bracts ca. as long as pedicels |
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(8) |
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| 8 (7) |
Racemes and short vegetative branches appearing simultaneously from growing branches of previous year; flowers white, less than 3 mm in diam.. |
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3 T. androssowii |
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Racemes appearing not simultaneously with vegetative branches; flowers pink, 4(-5) mm in diam.. |
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4 T. gracilis |
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| 9 (5) |
Flowers mostly 5-merous, but mixed with 4-merous ones on same raceme, blooming only in spring. |
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5 T. gansuensis |
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Flowers all 5-merous, blooming in spring, and also in summer and autumn (blooming 2 or 3 times) |
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(10) |
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| 10 (9) |
Petals completely open, deciduous after anthesis. |
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6 T. arceuthoides |
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Petals not completely open, persistent at fruiting stage, surrounding base of capsule |
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(11) |
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| 11 (10) |
Racemes often 2- or 3-clustered; petals contacting each other, apex incurved, and thus corolla globose. |
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7 T. hohenackeri |
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Racemes usually singular; petals nearly straight and ascending, or slightly open, apex recurved. |
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8 T. chinensis |
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| 12 (4) |
Flowers blooming in spring, then also in summer and autumn (blooming 2 or 3 times) |
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(13) |
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Flowers blooming only in summer or autumn |
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(17) |
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| 13 (12) |
Petals completely open, deciduous after anthesis |
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(14) |
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Petals not completely open, persistent in fruit, surrounding base of capsule |
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(15) |
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| 14 (13) |
Flowers blooming in spring 4-merous (occasionally 5-merous); those blooming in summer and autumn 5-merous, large and completely open, 4(-5) mm in diam.; filaments at apex of disk lobes; capsule 4-7 × 1-2 mm. |
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4 T. gracilis |
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Flowers all 5-merous, small, less than 3 mm in diam.; filaments between disk lobes; capsule less than 3 × 1 mm. |
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6 T. arceuthoides |
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| 15 (13) |
Petals not open, apically often incurved, contacting each other, and thus corolla globose. |
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7 T. hohenackeri |
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Petals slightly open, nearly straight and ascending, apically often recurved, and corolla not globose |
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(16) |
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| 16 (15) |
Branches soft, slender, long, pendulous; young branches with deep green leaves, slender, pendulous; leaves on upper branches half adnate, subulate to ovate-lanceolate, apex acuminate, incurved. |
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8 T. chinensis |
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Branches rigid, erect or obliquely ascending; young branches often with gray-green leaves; leaves oblong or oblong-lanceolate, apex acuminate, mostly recurved. |
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9 T. austromongolica |
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| 17 (12) |
Young branches and leaves hispid and puberulous. |
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11 T. hispida |
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Young branches and leaves glabrous or sparsely papillose |
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(18) |
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| 18 (17) |
Petals persistent after anthesis |
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(19) |
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Petals deciduous or partly so |
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(20) |
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| 19 (18) |
Filaments between disk lobes; petals straight, ascending, contacting each other, corolla cup-shaped. |
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10 T. ramosissima |
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Filaments at apex of disk lobes; petals abaxially raised, contacting each other, corolla globose. |
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12 T. jintaensis |
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| 20 (18) |
Petals all deciduous; racemes dense, forming a dense panicle; branches also dense. |
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13 T. leptostachya |
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Petals partly deciduous; racemes turning outward, forming a spreading panicle; branches also turning outward |
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(21) |
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| 21 (20) |
Young branches and leaves sparsely papillose; racemes 4-7(-15) cm; flowers dense, ca. 22 within 1 cm. |
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14 T. karelinii |
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Branches and leaves not papillose; racemes 3-5 cm; flowers lax, ca. 5 within 1 cm. |
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15 T. tarimensis |
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List of lower taxa
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