94 TREES AND TREE-PLANTING. 
a beautiful pea-green color and smooth surface. Its leaf 
is oval-shaped, terminating in a point, and deeply toothed 
on its edges. 
Some of the large specimens of this tree are to be 
found in Pennsylvania, specimens having been seen grow- 
ing on the Schuylkill River and in Philadelphia of the 
height of fifty feet and a four-foot circumference of 
trunk. 
Its seed, as soon as practicable after gathering, should 
be thickly sown, as about half of them are false, and not 
over one in ten will germinate. Sow in the fall in shal- 
low furrows, and cover only one and a half inches deep 
with earth. In somewhat moist and deep soil the plants 
grow rapidly, and should be protected, during the fall 
and winter, with a covering of straw. Plant them out in 
the spring four feet apart, and they will grow the first 
year ten to sixteen inches. I have seen nursery plants, 
two years old, six feet high and one inch in diameter. 
Box-elders of eleven years old measured thirty inches in 
circumference and were thirty feet high. 
A suggestion from Michaux says that, from its rapid 
growth, if cut down and “ layered” it might form a val- 
uable underwood, to be used for fuel, charcoal manufact- 
ure, and other purposes; but, on trial of this, it has been 
found that the “layer” soon decays. 
The introduction of this tree into England dates from 
1688, and since that time its growth has extended to the 
continent of Europe, where, especially in Austria, a spec- 
imen of it attained the excessive height of eighty feet. 
