698 Part IV. Chapter 7. 
sea-level. This formation consists of an extended saw-grass swamp (Cladium 
effusum) merging in places with pine land, prairies, cypress swamps, custard 
apple (Anona glabra) swamps and are by winding river channels, occa- 
sionally filled with water lettuce, Pzstia stratiotes, with the water Beer clear 
and pure, and covered with scattered arisankielinde, Its flora consists of 
grasses, sedges and other herbaceous plants, among which are many aquatic 
and mud-inhabiting species (f. e. Peltandra virginica, Saururus cernuus) less 
than one-half as many species as grow either in the hammocks or the pine- 
lands. This formation partially surrounds and intersects the sandrock ridge, 
Structurally it consists of a marsh with scattered hammocks, while its flora 
is composed of plants (Aplos tuberosa etc.) of far northern range and therefore 
mainly of a different character from those found in either the pinelands, or 
the hammocks, which are characterized by tropic palms, cycads, orchids and 
bromeliads. 
The shores of the streams by which the everglades are entered are covered 
with rank growths of the cocoa-plum, Chrysobalanus icaco. This same species 
grows about the edges of the glades producing blue fruit on the eastern edge 
and white fruit toward the west. 
Savanna- and Prairie Formation. With.the appearance of level plains by 
the removal of the shallow sea over a sandy bottom, the isolated trees, which 
associated together constitute the savanna formation, appeared and clothed the 
ground. Imperceptibly these savannas are transformed into pine-land. — 
en the swamps, or everglades are raised a few feet by the deposition of 
decaying vegetable matter and silt the character of the vegetation completely 
changes. Grassland is formed and the hard, rank grasses, palmetto scrub and 
reeds give place to growths of “blue joint”, Andropogon virginicus and other 
grasses (Syntherisma, Panicum virgatum) which can be used for fodder and hay. 
Pine Barren Formation. (See plate VI to page 306: Southern Florida.) 
When the grassland is invaded by trees, pineland results, if that invasion is 
sufficient to close up the grassy steifhes with a EBEN, forest growth. It 
may also be formed by the encroachment of trees on the savanna formation. 
P Inus car tbaea (= P. heterophylla = P. cubensis) is the dominant tree of the 
pine barrens associated with numerous shrubs, shrubby herbs and herbaceous 
perennials. The exposed coral rock of the slight elevations maintain not only 
more species than the slight depressions, but also more individuals, or in 
other words the more eroded and needle- shaped the condition of the coral 
rock with apparently barely enough soil to support plant life, the more diversi- 
fied and abundant the vegetation. Pinus clausa occurs in the pine scrub 
associated with Ceratiola ericoides. 
These ns are light and airy, the timber affording little shade. Besides Pinus caribaea 
several palms are conspicuous elements of the landscape, viz: Serenoa serrulata, Cocco- 
thrinax ju ae (= Thrinax argentea), C. Garberi (on dry coral ridges along Biscayne Bay), 
Sabal megacarpa (= S. Etonia), and Zamia floridana. The most abundant fern of the pine barrens 
is Pteridium aquilinum var. pseudocaudatum found in dry so 
