The Poplars (_Populus_) and the Willows (_Salix_) together constitute the Natural Order _Salicineae_. The two genera agree broadly in the construction and arrangement of their flowers in catkins, but whereas the Poplars have broad leaves and drooping catkins, the Willows, with few exceptions, have long slender leaves and erect catkins. The sexes are not only in distinct flowers, but on separate trees--what botanists describe by the term _di[oe]cious_. The males appear to be far more numerous than the females. In the popular sense there are no flowers, for there are neither sepals nor petals, each set of sexual organs being protected merely by a scale. The catkins containing these flowers usually appear before the leaves. As there is nothing to attract insects to the work, the trees have to rely upon the wind for conveying the pollen to the female trees. The first three species described below have from four to twelve stamens; _P. nigra_ and _P. fastigiata_ have from twelve to twenty stamens. The Poplars share the love of the Willows for moist places. They are found more frequently in gardens and hedgerows than in woods. Their growth is rapid, and their timber, consequently, is of little value, though its softness and lightness render it suitable for making boxes, and its whiteness and non-liability to splinter fit it for use as flooring. An additional point in favour of White Poplar for the latter purpose is its unreadiness to burn. [Illustration: White Poplar, or Abele. A, female catkin.]