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 consideration 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 arranged as nearly as possible in order of abundance, the most abundant 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 wN rongly 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 incomplete 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, I8)
Wherever there are shallow bays or lagoons of salt water, protected 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 southward.