.
The Salicales or willow order of flowering plants, is comprised solely
of the Salicaceae family. The Salicaceae family is further
divided into two genera, Salix (willow) and Populus (poplar,
aspen, cottonwood). The two genera are comprised of around 320 (Salix)and
30 species (Populus). The Salicaceae family are trees and shrubs
found predominantly in the Northern Hemisphere. Only one species ( S.
tetrasperma ) is native to tropical/subtropical regions. [ ]
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Willow ( Salix )
Shrubs and trees of the genus Salix and Salicaceae family.
Generally native to northern temperate regions and commonly used for ornament,
shade and timber as well as being the source of salicin (salicylic acid),
which is used in pain relievers (aspirin is a derivative of salicylic
acid). All species of the salicales family (willow and populus) have catkins,
male and female on different trees, and seeds with long, silky hairs.
The largest willows are the black ( S. nigra ), the crack, or brittle
( S. fragilis ) and white ( S. alba ) willow, all of which can
attain 20 metres (65 feet) or more. Weeping willows refer to those species
and hybrids of willow with a 'drooping habit', especially S. babylonica
and its varieties from East Asia. [ ]
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Poplar (Populus)
Poplars are common trees in the cooler regions of the Northern Hemisphere
and are often used to line avenues or to form windbreaks. Poplar wood
is also commercilly important as it is used for plywood, pulp and matches.
The soft, white wood of Populus is fabricated into plywood, pulpwood,
excelsior, boxes, and matches. As with all other members of the salicales
family, Populus catkins are male and female on different trees
and their flowers contain no petals or sepals. Populus are generally insect
pollinated but certain species are also wind-pollinated. Populus
differ from Salix in that the leaves are roughly triangular in
shape while Salix leaves are more often linear. [ ]
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[1] The Encyclopaedia
Britannica Online : |