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2. Populus Linnaeus, Sp. Pl. 1034. 1753; Gen. Pl. ed. 5. 456. 1754; Andersson in DC., Prodr. 16(2): 323. 1868; Boiss., Fl. Or. 4: 1192. 1879; Hook. f., Fl. Brit. Ind. 5: 637. 1888; R. Parker, For. Fl. Punj. ed. 3: 508. 1956; A. Neumannn in Rech. f., Fl. Iran. 65: 1. 1969; R. R. Stewart, Ann. Cat. Vasc. Pl. W. Pak. Kashm. 180. 1972; Meikle, Fl. Cyprus 2: 1489. 1985; F. Zhenfu, Z. Shidong & A.K.Skvortsov in Wu Zeng-yi & P. H. Raven, Fl. China 4: 139. 1999.
Deciduous trees. Buds with several unequal scales. Leaves alternate; petiole usually long, terete or flattened, lamina entire or lobed, linear to rhombic ovate, dentate, serrate; often dimorphic on long and short shoots. Flowers appearing before leaves, anemophilous, in elongate, cylindrical, pendent, pedunculate catkin. Each flower in the axil of a laciniate or toothed bract; pedicellate; disc cup-shaped. Stamens 4-many, filaments free. Ovary sessile, unilocular, surrounded at the base or up to three quarters of its length by the disc; ovules many on 2-4 parietal placentas, style short, stigmas 2-4. Capsule 2-4 valved; seeds minute, numerous, with a long dense tuft of silky hairs.
A genus with c. 100 species, distributed mainly in north temperate regions of the world; represented in Pakistan by 6 taxa.
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| 1 |
Lamina lobed (or sometimes narrowly oblong and entire on young plants and suckers) buds pubescent, not sticky. |
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(2) |
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Lamina not lobed, buds sticky. |
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(3) |
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| 2 (1) |
Lamina morphologically very variale, glabrous. |
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4 P. euphratica |
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Lamina always lobed white tomentose beneath. |
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2 P. alba |
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| 3 (1) |
Stigmas 2, sessile. Capsule 2-valved. |
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(4) |
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Stigmas 3-4; capsule 3-4 valved. |
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(5) |
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| 4 (3) |
Lamina 2-7 cm long, 3-7.5 cm broad, female catkin up to 7 cm long. |
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1 P. afghanica |
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Lamina 5-12 cm long, nearly as broad, female catkin up to 10.5 cm long. |
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6 P. nigra |
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| 5 (3) |
Lamina 7-18 cm long, 6-13 cm broad, base usually cordate, catkin in fruit, 15-30.5 cm long, capsule pedicellate (pedicel 2.5-10 mm). |
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3 P. ciliata |
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Lamina 4-10.5(-18) cm long, 3-9 cm broad, female catkin in fruit 6-10 cm long, capsule subsessile (pedicel 1-1.5 mm). |
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5 P. pamirica |
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Lower Taxa
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