30 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. « [Bull. 
DISTRIBUTION OF THE BRYOPHYTES IN CON- 
NECTICUT ACCORDING TO ENVIRONMENT 
Even to the casual observer it is evident that the character 
of the vegetation which clothes the surface of the earth varies 
greatly under different conditions. There is a marked con- 
trast, for example, between the impenetrable tangle of a 
tropical jungle with its wide diversity of species, and the 
northern spruce forests which are relatively open and are made 
up of comparatively few species. The vegetation at the sum- 
mit of Mount Washington is scant and limited to shrubby 
and herbaceous plants, while the valleys but a few thousand 
feet below are heavily wooded. ‘Ordinary land plants differ 
strikingly in appearance from seaweeds and other submerged 
aquatics. 
These are perhaps extreme illustrations, but innumerable 
examples of this adaptation to environments which are less 
diverse may be seen everywhere. The vegetation in an open 
field presents a decided contrast to that of a pine grove but 
a few hundred yards distant, while the flora in a bog is totally 
different from that in a meadow. 
It may be. stated as a general rule that every plant is best 
adapted to a peculiar environment, and that for every species 
there are’ certain more or less well defined limits outside of 
which it cannot exist. What is true of the higher plants applies 
even more forcibly to the: Mosses and Hepatics, for, as Les- 
quereux remarks, “ these humble and apparently useless beings 
have their geological and lithological preferences far better 
marked than any other kind of vegetable.”* 
The factors which produce this environment and determine 
these limits are numerous, but the following are the most 
important: 
I. Latitude. 
II. Altitude. 
III. Character of the substratum. 
IV. Intensity of the light. 
V. . Water supply. 
*Quoted by Mohr: Plant Life of Alabama. Contr. U.S. Nat. Herb., 6: 292. r9gox. 
