232 FLORIDA GEOLOGICAL SURVEY—THIRD ANNUAL REPORT. 
In describing each type of swamp or other peat deposit the 
plants growing in it are listed, for the vegetation is always the 
most important feature of such places, and as a rule the peat has 
been formed from essentially the same species of plants which are 
now growing on or near it. Our oldest peat (leaving out of con¬ 
sideration the fossil peat which is buried under several feet of 
sand, etc.) is probably not more than a few thousand years old, 
and the vegetation of Florida as a whole has probably not changed 
much in that length of time, though of course there have been many 
changes in local details, as the peat deposits increase in area or 
depth. 
In most of the following lists the plants are divided into trees, 
shrubs, herbs and mosses, and the species in each of these groups ar¬ 
ranged as nearly as possible in order of abundance, the most abun¬ 
dant or conspicuous ones always being mentioned first. Those 
seen only once or twice in any one kind of swamp are usually 
omitted, for there is always a possibility that such plants do not 
properly belong to the habitat in question, or that they have been 
wrongly identified; and, furthermore, rare plants are not of much 
significance in quantitative studies of vegetation. It is scarcely 
necessary to remark that all of these lists are more or less in¬ 
complete or otherwise defective, because of the limited time which 
I have had for field work, and the fact that most of it was done 
in the winter and spring months, while many of the plants can 
be indentified with certainty only in late summer or fall. 
In listing the plants the use of technical names is necessary, 
for the reasons stated in the preface. Common names, where 
known, are also inserted, to save the non-botanical reader the 
trouble of looking up each technical name in the index and then 
in the systematic catalogue of plants, where the same common 
names are given again. 
MARINE MARSHES AND SWAMPS. 
(plates 17, iB) 
Wherever there are shallow bays or lagoons of salt water, pro¬ 
tected from waves, extensive deposits of peat or muck are formed 
by a type of vegetation quite distinct from that of fresh water. In 
temperate regions the great bulk of the salt water vegetation is 
composed of herbs, forming marshes, while in the tropics woody 
plants are much more numerous in such places, and we find swamps 
instead. Both types are pretty well represented in Florida, the 
marshes in the northern parts of the state and the swamps south¬ 
ward. 
