Of the European kinds one of the most important and best marked forms is the white poplar or abele, P. alba, a tree of large size, with rounded spreading head and curved branches, which, like the trunk, are covered with a greyish white bark, becoming much furrowed on old stems. The leaves are ovate or nearly round in general outline, but with deeply waved, more or less lobed and indented margins and cordate base; the upper side is of a dark green tint, but the lower surface is clothed with a dense white down, which likewise covers the young shoots - giving, with the bark, a hoary aspect to the whole tree.
Piles of elm, oak, white poplar or larch were driven into this clay to the depth of 16 to 20 ft.
Bicolor); lentils, peas, beans, vetches; cotton, hemp, safflower, tobacco; Medicago sativa (for horses); cucumber, melons, water-melons, figs (those of Sinjar famed for sweetness), dates (below, 'Ana and Tekrit); a few timber trees; plane and white poplar (by streams), willow and sumach (by the Euphrates).
Campestre), the hornbeam and the black and white poplar are very common.
The white poplar is an ornamental tree, from its graceful though somewhat irregular growth and its dense hoary foliage; it has, however, the disadvantage of throwing up numerous suckers for some yards around the trunk.