THE BLACK POPLAR. 455 
habit, and of a dark red colour. The female 
catkins are round—the seed which they produce, 
ripened by May, being enclosed in round capsules, 
and beautifully covered with white cotton-like 
down. Another mark by which this species can 
be distinguished from the others is the knotty 
character of its trunk. 
So rapid is the growth of the Black Poplar that it 
will oftentimes attain a height of as much as forty 
feet in ten years. But it is owing to this some- 
what exceptional rapidity of growth that the 
timber of Populus nigra is very soft and fibrous, 
being of little use save for the manufacture of 
packing-cases. It is not a long-lived Tree, reach- 
ing its perfection in half a century, and com- 
mencing to decay after periods, beyond that age, 
varying from ten to thirty years. The yellow 
colour of its decaying leaves, taken in conjunction 
with their peculiar character of restlessness, add to 
it a noticeable feature in the mass of autumnal 
colouring. 
