56 
WAYSIDE AND WOODLAND TREES. 
In most trees the leaf-stalks are flattened from above, but in 
the case of the Poplars they are flattened from the sides, so 
that when moved by the wind they flutter laterally. These 
leaves have a waved margin, a smooth upper surface, and 
are snowy white and cottony beneath. The leaf-buds are 
also invested by cottony filaments. The roots produce numerous 
suckers, even at a distance from the trunk, and the leaves 
on these sucker-shoots are very large— two to four inches broad 
— of a more triangular shape, the outline lobed and toothed. 
The catkins, which appear in March and April, are cylindrical ; 
those of the male trees may be as much as four inches long, 
each flower containing from six to ten stamens with purple 
anthers. The female catkins are not nearly so long, the two 
yellow stigmas are slender with slit tips, and the ovaries 
develop into slender egg-shaped capsules, each with its fringed 
scale. This species is said not to produce flowers in Scotland. 
In July, when the seed capsules open, the surrounding vege- 
tation and ground are thickly strewn with the long white cotton 
filaments attached to the seeds. The wood of this tree is softer 
and more spongy than that of other Poplars. 
The Grey Poplar {Populus canescens), which is thought to be 
indigenous only in the south-eastern parts of England, is not 
so tall a tree as P. alba, though it sometimes attains to eighty 
or ninety feet, with a circumference between ten and twent)'- 
four feet. Its life extends to about a century, but its wood 
— which does not split when nails are driven through thin 
boards of it— is considered best between fifty and sixty years 
of age. The leaves on the branches are shaped like those of 
P. alba, but their under sides are either coated with grey 
down or are quite smooth ; those of the suckers have their 
margins cut into angles and teeth. The female flowers mostly 
have four wedge-shaped purple stigmas (sometimes two), which 
are cleft into four at their extremities. 
The Aspen or Asp {Populus tremuld) does not attain either 
