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BLACK ALDER. 
Alnus glauca. A. folds subrotundd-ellipticis, duplicatd-serratis, siibtus glaucis. 
Alnus incana. Willd. 
This species of Alder, which is unknown in the Southern, and rare in 
the Middle States, is not uncommon in Massachusetts, New Hampshire and 
Vermont ; but even here it is less multiplied than the Common Alder, 
which abounds throughout the United States. The Black Alder is a third 
taller than the preceding species, being sometimes 18 or 20 feet in height, 
and about 3 inches in diameter. Its leaves are similar in shape, but are 
easily distinguishable by their different tint and superior size : they are of a 
pale bluish green, and a third larger than those of the Common Alder. 
Both species grow in cool, moist places, and upon the margin of rivulets. 
The bark of the trunk and of the secondary branches is smooth, glossy, 
and of a deep brown color sprinkled with white. It is employed by hatters, 
if I have been correctly informed, for dying black. The diminutive size 
of this tree excludes it entirely from use ; but to recommend it to the notice 
of amateurs it is only necessary to observe that it is one of the most beau- 
tiful species of the genus. 
The dwarfish stature of all the species of Alder that have hitherto been 
discovered in North America, excludes them from that class of vegetables 
to the description of which I have restricted my labors ; but I could not 
forbear mentioning the two most remarkable species, of which one merits 
attention on account of its abundant diffusion, and the other on account of 
a striking peculiarity in the color of its leaves. 
PLATE LXXVL 
Black Alder , with a leaf of the natural size. 
