BIRCH FAMILY 
tial oil identical with that obtained from Gawltherta pro- 
cumbens, and which under the name of Wintergreen Oil is 
employed as a remedy for rheumatism. The remedial 
agent is salicylic acid, of which it contains a large percen- 
tage. 
The wood when first cut has a beautiful rosy tinge which 
deepens with age and exposure. The difference between the 
annual circles gives it a general clouded appearance and this 
is especially marked in a section taken from the point of 
union of a large limb with the body of the tree. When such 
a piece is skilfully stained and polished, it closely resembles 
mahogany. Asa matter of fact, all good imitations of ma- 
hogany are birch. However, the wood is beautiful enough 
to have a value of its own. 
ALDER 
Alnus glutindsa, 
The northern native alders east of the Rocky Mountains 
are shrubs, following the water-courses and nowhere attain- 
ing the arborescent form. They are aquatic, enjoying situa- 
tions too wet for either willow or poplar. 
The only alder tree which is commonly found in the northern 
states is A/nus glitinosa, a European species which is fairly 
naturalized. It is native to the entire continent of Europe 
and although naturally aquatic will grow in good soil, some- 
what removed from water. 
The leaves are orbicular, obtuse, wedge-shaped at base 
and serrated at margin. When young the leaves and stems 
are somewhat glutinous, whence the specific name. The 
bark is dark and furrowed, and the wood is valuable for but 
one purpose. It will not endure alternate wet and dry, but if 
constantly submerged it becomes extremely hard and virtu- 
ally incorruptible. 
The flowers are moncecious, the staminate blossoms are long 
drooping catkins which form in the late summer and hang 
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