TRANSACTIONS OF WAGNER 
188 VEGETATION OF SOUTH FLORIDA 
end of this elevation, it was invaded by the long-leaf pine forest, which already 
covered the northern central part of the state. Therefore, in all probability, 
the slash-pine forest is of southeastern origin, the long-leaf pine forest of north- 
ern. The first occupied the Lower keys and Miami region of the mainland, 
invading the higher newly elevated ground in southwestern Florida. The 
second forest merely extended itself southward, as rapidly as the land was 
elevated. Along the Caloosahatchee River, therefore, we find an interdigi- 
tation of the forests of the two trees as previously emphasized. 
The immediate coast line of the peninsula with sandy deposits in the form 
of beach sand and dune sand was occupied by beach and thicket plants, while 
mangrove swamps covered the lower levels and assisted materially in the ad- 
vancement of the coast line. The ancient dunes of the east coast had their 
genesis in the sand blown inland from the coast. It buried the ancient slash- 
pine forest, as is evidenced by the flat pineland, lakes, and marshes, which 
exist between the dunes at the old level. These inland sand dunes were covered 
by the rosemary scrub type of vegetation, where Pinus clausa (Engelm.) Vasey, 
Ceratiola ericoides Michx., and associated species are prevalent. An ancient 
lake of which the present Lake Okeechobee is a dwindled portion covered the 
basin now occupied by Lake Okeechobee and the surrounding Everglades. 
This ancient lake was bordered by prairies and cypress swamps, the present 
location of which is determined by following the shore line of that ancient lake. 
With the exception of the cypress heads along the main rivers of the region, all 
the large bodies of cypress in South Florida at the present time follow approxi- 
mately the ancient limits of the older and greater lake. As the waters in the 
southern end of the ancient Lake Okeechobee were shallow, they were gradually 
converted by the growth of the saw-grass and other plants into the vast marsh, 
now designated as the Everglades. With the formation of the Everglades, the 
plant formations of South Florida reached much their present condition, posi- 
tion, and floristic character. Arranging the formations in the order of their 
probable appearance in South Florida, we have: 
Beach and Dune Formations. 
Mangrove Swamp Formation. 
Long-leaf Pine Formation (west coast). 
Slash-Pine Formation (east coast and Lower keys). 
Hammock Formation. 
River Bank Formation. 
