1906] GANONG—NASCENT FOREST OF MISCOU BEACH 93 
Myrica carolinensis, which comes to form dense discoid (sometimes 
almost fairy-ring like) masses on the crests and inner slopes; and 
the less frequent, low, dense-tufted, white-hairy shrub, Hudsonia 
tomentosa, in irregular close patches. All of these plants are pro- 
nounced xerophytes, which amply explains their ability to live in 
this situation, and even their preference for the somewhat drier 
upper slopes of the dune beaches. Their xerophilism, in common 
with that of many other evergreen sand plants, is, as I guess it, an 
Fic. 7.—Typical upper inner slope of a dune beach; the grass is beach grass, but 
6 
in the center is a typical plant of dwarf creeping juniper. 
adaptation to he physiological dryness which results when, as 
must often be the case in spring and fall, the ground. water is of 
low temperature and hence slowly absorbed, while the leaves are 
€xposed to high transpiration conditions from the bright sun, heat 
reflected from the sand, and high winds.® The juniper, while 
perfectly at home here, apparently is so only through coincidence, 
for its original habitat is seemingly dry rocky hills. But the other 
° This principle, which from its discoverers we may call the Kra~mMan-GOEBEL 
Drincinia 
Principle, seems to me dese srving of much more recognition than our students are 
in 
nclined to give it. At least it calls for careful experimental investigation. 
