POPLAR. 278 
Populus alba canescens. Silver Poplar. 
This differs from the above in having leaves broad or nearly 
circular in general outline, notched but not lobed, but like it in 
that the leaves and young shoots are downy. 
Populus alba bolleana. Bolle Poplar. 
A form of the White Poplar of the same narrow upright 
habit of growth as the Lombardy Poplar 
Leaves somewhat deeper lobed but with the 
same cottony covering. It differs from the 
common White Poplar in that it does not 
sucker from the root and is more difficult to 
propagate from cuttings, which require to be 
calloused before planting. It is striking in 
aspect, and should be used sparingly in orna- 
mental planting. 
Figure <9: Leaf 
of Bolle Poplar. Populus laurifolia. (P. certinensis.) 
One-third natural is i 
size. Certinensis Poplar. 
Leaves on the old wood or slow growing twigs are very dil- 
ferent from those on vigorous growing shoots. The former are 
broadly oval, with finely serrate margins and on cylindrical 
twigs. The strong shoots are deeply angled or grooved, and 
the foliage on them is wavy in outline. The trees are some- 
times confounded with the Cottonwood, from which they are 
very distinct, especially in the leaves, which are on shorter more 
rigid petioles. A large tree of rapid growth. 
Distribution.—Introduced from Russia. Probably a native of 
northern Europe and Siberia. 
Propagation.—Easily grown from cuttings. 
Propertics of wood.—Light, soft, easily worked and reported 
as being valuable for many of the purposes for which pine tim- 
ber is commonly used. 
Uscs.—The Certinensis Poplar has been tried largely in this 
section, and has proved to be a good, quick-growing tree for 
prairie planting. In some localities, however, it has been in- 
fested with a borer which has occasionally done much injury, 
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