1920] The Land of Ferns 93 



careous sand, active along the coast, stationary back of the coastal 

 lagoons and in the interior. Sheli-monnds or kitchen-middens are 

 usually bnilt on or near dunes. The so-called "scrub," which com- 

 prises extensive areas of white sand supporting a characteristic plant 

 association, is included here. 



In these various areas are found about one-third of the different 

 kinds of ferns and fern-allies growing naturally in all America north 

 of Mexico ; and the variety in habit and leaf-form of these far exceeds 

 that exhibited by the ferns of any other part of either the United 

 States or Canada. In Florida more than one hundred ferns and fern- 

 allies, both simple and complex, from very small to gigantic, grow 

 either as native or as naturalized plants. 



There are ferns in nearly every part of the State, but only the more 

 marked areas of distribution will be referred to on the following 

 pages, to-wit : northern Florida is the long horizontal (east-west) axis 

 of the State, while peninsular Florida is the long perpendicular 

 (north-south) axis. The Florida Keys'^ are the islands of the Florida 

 reef off the southern coast. The Everglade Keys are islands in the 

 southern part of the Everglades. The Florida Keys and Everglade 

 Ke.ys are islands of rock. The upper series of Florida Keys are of 

 coral limestone and are clothed with hammock. The Everglade Keys 

 and the lower series of Florida Keys are of oolitic limestone and are 

 clothed with both hammock and pine forest. The lime-sink region is 

 an area in the northwestern part of the peninsula, which is surrounded 

 by other phytogeographic regions. It comprises mostly rolling sandy 

 pine woods with depressions or sinks, but only few streams. How- 

 ever, near the rivers there are many large springs. 



The different kinds of fern worts may be grouped thus: (a) natur- 

 alized exotic species, (b) endemic species, (c) species typically of a 

 more northern distribution, and (d) species typically of more south- 

 ern distribution, and consequently tropical. 



There are, apparently, only three naturalized fernworts. These 

 are : 



Pycnadoria loiifrifolia (Bracken) 

 Dryopteris sotigora (Wood-fern) 

 .Marsilea vestita (PepperAvort) 



'Key (Simnish cnyo, English rny) priiiiiirily ai)|>lie(l to islands alonp the coast in and 

 near Sjianish speakins countries. largely rej'laces the use of the word "island." particularly 

 in southern Florida, and hy the inhabitants is applied to islands in the Everglades us 

 well as to the islands of the coast and reef of Florida. 



