I50 BOTANICAL GAZETTE [AUGUST 
are precipitous, due probably to water action during the post- 
glacial submergence (5). The northern half of the island is com- 
paratively level. The topography therefore offers a diversity of 
habitats. 
The climate of the island is a curious mixture of the marine and 
the inland, the former, of course, predominating, but the latter 
being found in places shut off from the ocean winds. On the north- 
east side of the island the average annual precipitation is 48.3 
inches, of which 16.1 inches or one-third comes in the growing 
season (May-—September inclusive). This should be abundant, 
but there are periods during the summer in which lack of moisture 
is an important factor. 
The mean annual temperature is 44° F., running from 21° in 
January to 65.5° in July. The sea tends to keep the temperature 
uniform, but it is uniformly cold, for it is beyond the Gulf Stream. 
_ There are surprising fluctuations in temperature, however. The 
large areas of exposed granite rock take up and radiate great 
quantities of heat, so that the fluctuations, particularly in places 
cut off from the ocean winds, must have a distinct bearing on the ~ 
vegetation. 
: The vegetation, although predominantly northern, contains a 
_ strong mixture of middle Atlantic elements. It contains not only 
plants but forest associations belonging to both the boreal and the 
_ transition zones (4). Furthermore, this island and Schoodic Point, 
a small peninsula about ro miles to the eastward, are isolated 
- stations for Pinus divaricata. 
_ The forest associations of the island are 5 in number: (1) 
_ spruce, (2) white pine, (3) cedar, (4) pitch pine, (5) grey birch- — 
aspen. Over most of the island, except the parts recently burned, 
ae the first 3a associations mingle in a rather confusing manner to form a : : 
oe eae iotest containing eee di Proportions of red spruce, balsam fir, 
ne, and white cedar, with an admixture of red maple, grey 2 
