220 Harper: THE ‘‘Pocosin” oF PIKE CouNTy, ALA. 
two pines here listed prefer richer soils than all the other southern 
pines and some deciduous trees. 
Although it is digressing a little from the scope of this paper, 
it is interesting to note that the hammocks and river-bluffs of the 
Altamaha Grit region of Georgia* differ from each other in much 
the same way that the pocosin does from the bluffs, etc., just 
mentioned. Both hammocks and river-bluffs are covered with 
climax forests, but the soil is sandy in one case and loamy in the 
other, which makes considerable difference in the vegetation. 
From the frequency numbers which have been published in the 
work cited, it appears that 79.6 per cent. of the trees and 30.5 
per cent. of the shrubs in the hammocks are evergreen; while the 
corresponding figures for river-bluffs are 37 and 15; a difference 
whose significance was not suspected until long after these Georgia 
lists were published. The sand-hills which border the Georgia 
hammocks and protect them from fire have been estimated in the 
same way to have 28.2 per cent. of their trees and 48.3 per cent. 
of their shrubs evergreen. 
SUMMARY 
This so-called pocosin (which has little in common with the 
typical pocosins of North Carolina) is a many-storied climax forest 
of a type characteristic of dry sandy soils in the coastal plain of 
Alabama, Georgia, and northern Florida. The accumulation of 
humus—and consequently the development of climax vegetation— 
began in ravines, and has been favored by the protection from fire 
afforded by the sparseness of the surrounding pioneer vegetation. 
Something like half of the woody plants of the pocosin are 
evergreen, which is evidently a larger proportion of evergreens 
than in the case of the pioneer vegetation of the same soil and of 
the climax vegetation of soils richer in mineral plant food in the 
same region and elsewhere. 
Each fundamentally different type of soil seems to have its 
own characteristic pioneer and climax vegetation; and the pro- 
portion of evergreens in this case—if not in many others—increases 
with normal succession, owing probably to the lowering of soil 
temperatures during the growing season, and to the locking up of 
plant food in undecayed leaves or sour humus, among other 
things. 
* Ann. N. Y. Acad. Sci. 17: 98-109. 1906. 
