TREES HAVING SIMPLE LEAVES 107 
use except for fuel and paper pulp, but there the like- 
ness ends. 
To this family belongs the quaking aspen, whose 
- leaves are continually trembling,—in fact, the whole 
family is a restless one, the constant motion being due 
to the shape of the long stems, which are flattened. 
The people of Scotland have a 
superstition that it was of aspen 
Aspen Aspen Poplar, 
or Large-Toothed Aspen 
Fie. 117 
wood that our Saviour’s cross was made, and that the 
tree shivers in constant remembrance of that fact. 
Beside the quaking aspen is the large-toothed aspen, 
the Lombardy poplar, and the cottonwood. 
