110 



OUTLINE OF PLANT GEOGRAPHY 



The southern prairies are drier than those of the north, the 

 region having very hot summers, and there is a considerable 

 development of annual species such as characterize the desert 

 and semi-desert regions of the far western states. 



Florida 



The only part of the United States which can be called tropical 

 is the southern part of Florida and the "keys" south of it. The 



climate is a hot humid one, 

 Hkl and the vegetation is to a 

 great extent West Indian in 

 composition. 



The eastern part of the 

 Florida peninsula is mostly a 

 sandy plain with coral rock 

 near the surface. The gritty 

 soil is covered with a thin 

 growth of coarse grass, and 

 toward the south, the saw- 

 palmetto {Serenoa serrulata), 

 is very abundant as an under- 

 growth for the pines which 

 form an open forest. The 

 principal species is the West 

 Indian P. Caribaea. 



A common plant of these 

 southern pine-barrens is a small 

 eye ad (Zamia Floridana), 

 which with a second species 

 growing in moister situations 

 are the only cycads found in 

 the United States. 



Inland is the extensive re- 

 gion of the "Everglades," 

 formerly impenetrable swamps covered with a dense growth of 

 saw-grass (Cladium effusum). Here and there are streams which 

 lead into the interior of this great swamp. Sometimes there are 

 areas of more elevated land covered with pine woods, and there 



Fig. 25. — Open pine forest (Pinus Cari- 

 baea) ; undergrowth of saw palmetto, 

 Miami, Florida. 



