1920] The Land of Ferns 99 



clence of reductioii are not hard to observe. These islands have been 

 worn down and washed away not only by the never-ceasing action of 

 the sea, but also by the hurricanes of ages. This is quite evident. 

 The rock surface, particularly in the case of the Lower Keys whose 

 limestone corresponds to that of the Everglade Keys, is polished off 

 and plate-like, instead of merelj- leached out and honeycombed. What 

 the former fernworts consisted of we cannot even imagine, but we are 

 safe in assuming that the list was more extensive than that which we 

 are able to record there now. 



The Everglade Keys, the second tropical area — a phytogeographic 

 region isolated in the Everglades — comprise a curved series of lime- 

 stojie islands appearing on the surface about the neighborhood of the 

 Miami River, trending southwest and disappearing in the southern 

 end of the Everglades. The area is surrounded by the Everglades, 

 except where a portion fronts on Bay Biscayne or its lagoons. 



As on the Florida Keys, the native flora of the Everglade Keys 

 consists almost wholly of tropical plants. Pineland predominates 

 in extent of area today; but the few hammocks — evidently themselves 

 remnants of a once dominant and magnificent forest — still harbor 

 nearl}^ fifty kinds of our tropical ferns. And among these are no 

 naturalized exotic species, no typically northern species. The only 

 northern ferns in the vicinity are those occurring where the Ever- 

 glades and the limestone islands meet. 



The number of ferns and fern-allies in this region is quite re- 

 markable when we consider that the area involved comprises onlj* a 

 few hundred square miles, a mere fraction of the State's large area. 

 Although variety in soil and other physical features is slight, this 

 area harbors more than fifty per cent, of the fern flora of Florida. 



An overwhelming majority of the species are typically tropical 

 American. In addition to these, there are several cosmopolitan spe- 

 cies and a few endemic ferns. Th(> plants of nearly one-third of the 

 species are epi[)hytic, living on the moisture of the air and getting 

 solid food from the bark and suiall quantities of humus, while an- 

 chored on trees and j)rostrate logs. This condition doubtless nuikes up 

 to some extent for the lack of variety in tojiography, climate, and soil. 



The Everglade Keys consist of two main divisions, the Biscayne 

 pineland^i and the Long Key itinehind. The loniifr group is made 



"These two «r(iiips ui islamls arc sciiaralnl ironi ruth oiluT liy a (listiincf ol three 

 miles. The interveiiiiii; KviTclades contain a niiiiihcr of slouRhs ' whifli rei)resent the 

 ui>|>er reaches of an uiiiiiaii|)(Ml rivor that flows southward and empties into the Bay of 

 Florida. The larger or eastern Kroiii) of islands takes its name from Bay Biscayne which 

 washes the shores of one of the islands for a distance of about fifteen miles. The smaller 

 Krimj" takes its name from LonK Key, the larKCst island IviiiR west of the slouehs referred 



In .•ll.i.v.v 



