147 
of the coastal plain, too, at least as far inland as Jefferson C ounty, 
Alabama. There the characteristic spindle-shaped northern form 
abounds in old fields and rocky pastures between Birmingham 
and Bessemer, and the Florida form with loose drooping twigs 
is scattered through the flatwoods southwest of Bessemer, where 
it is well shaded by tall oaks and hickories. 
In the numerous descriptions of the habitat of the cedar in 
the northern United States little or nothing is said about its 
having any particular fondness for lime. But in Alabama and 
adjoining states, where it is most abundant on limestone rocks, 
it is generally regarded as a lime-loving tree.* If it is, though, 
it differs strikingly from all other lime-loving trees of Eastern 
North America in having scale-like evergreen leaves, which is 
supposed to be a xerophytic adaptation. Ап explanation of 
its apparent fondness for lime will be suggested presently. 
Notwithstanding the great adaptability of the cedar to diverse 
conditions of soil and climate, there are in eastern North America 
four rather widespread classes of natural habitats where it is 
conspicuous by its absence: (1) the great northern coniferous 
forests, extending from New Brunswick westward; (2) the com- 
mon dry woods with oaks and hickories, which are represented 
in nearly all the eastern states; (3) the prairies, extending from 
Indiana westward; and (4) the pine-barrens, including the Pinus 
rigida barrens of Long Island and New Jersey, the P. palustris 
barrens from North Carolina to Texas, and the P. Caribaea 
barrens of South Florida. 
Now if the various habitats of our tree can be found to have 
any one character or combination of characters in common, not 
shared by the other habitats just named, we will have the key to 
the situation. 
One such character stands out prominently. The coniferous 
forests, dry woods, prairies and pine-barrens are burned over 
at intervals of a few to several years (the fires being set oftener 
now by man than they were by lightning and other natural causes 
in prehistoric times), while the habitats affected by the cedar are 
rarely or never visited by fire. 
* See bibliography at end of this paper. M 
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