276 Trees for Shade and Ornament 
attractive, short-lived, native White Birch (B. popultfolia Ait. (167)), so 
common in New England, which is of use only when treated as a shrub. 
A purple-leaved variety (airopurpurea) is very fine for color effect. 
B. papyrifera Marsh. (168), Paper Birch, the most northern native 
tree species, is quite different from the above, with a sturdier, stouter, 
more open branch system, and large, oval foliage, handsome in a differ- 
ent way, and worthy to be planted in northern grounds more than it is, 
especially in combination with evergreens and variously colored decidu- 
ous trees for winter effect. A distinct and most pleasing form with 
narrow, glossy leaves and pendulous habit was found by the writer 
near Quebec. 
Of the gray birches, two species, both native to our northern woods, 
have their ornamental value, differing mainly in the color of their bark. 
B. lutea Michx. (169), Yellow or Gray Birch, a stately tree, growing 
to large dimensions, of roundish outline. The small spurs or twigs 
from which the foliage develops give it a lively winter aspect, to which 
is added in older trees the pleasing effect of the bark of yellowish, sil- 
very hue (from which the name), peeling off in very fine layers and 
curling back, giving it a somewhat shaggy, interesting appearance. 
The branch habit is upright and stouter than in the white birches, and 
the outline oval. The simple foliage is peculiarly arranged in pairs. 
It is adaptive to heavy clay soils, but also to lighter ones, less light-need- 
ing than the white birches, but as rapidly growing. It is best used in 
single specimens in places where its large size can be accommodated. 
B. lenta Linn. (170), Cherry or Sweet or Black Birch, is a medium- 
sized tree, of somewhat more southern distribution, hardly distinguished 
in its foliage from the former, but with a somber, dark, close bark, 
resembling that of a black cherry when young, and not, or hardly, peel- 
ing; of regular, graceful, roundish outline, and sometimes with pendu- 
lous branches. It is adaptive to wet soils. 
BOX 
Buxus, the well-known evergreen, is represented by a number of 
species of small trees and shrubs, two of which, with several varieties, 
are in cultivation. They are mostly trained into shrubs, especially 
useful for borders and hedges, capable of being sheared into any form, 
which has led to the well-known aberrations in formal gardening. 
Their shade-endurance makes them desirable for under-planting. 
