102 JorKXAL OF THE Mitchell Society [June 



Okeediobeo. Here vegetatio]i is protected ])y the tempering of the 

 westerly winds, that blow across the lake in winter. As a consequence 

 the Boston-fern {Nephrolepis) and the strap-fern {Campyloneurum), 

 as well as some epiphytic orchids, are abundant. 



The third tropical fern area — and the one by far most difficult to 

 understand or to interpret satisfactorily — is that district several hun- 

 dred miles north of the Everglade Keys previously referred to, the 

 lime-sink region in the northwestern part of the peninsula. Here the 

 hammock is composed of trees not tropical, but characteristic of more 

 northern warm temperate regions. The trees are mostly deciduous- 

 leaved. There one finds iron-wood (Carpinus), oak {Quercus), elm 

 (Ulmus), sugarberry (Celtis), mulberry {3Iorus), sweet-gum {Liqui- 

 dambar), ash-leaved maple {Negundo), maple (Acer), and flowering 

 dogwood (Cynoxylon) . The boulders, sinks, chasms, canons, caves, 

 and cliffs hidden in these hammocks support a growth of ferns, even 

 if of a fewer number and of less variety, yet, just as tropical, both 

 in character and in kind, as do the lime-sinks of the Everglade Keys. 

 There is one striking difference, it is true. This is the absence of the 

 epiphytic kinds so common to the more southern area. The resurrec- 

 tion-fern {Polijpodium polypodioides) is the only truly epiphytic kind. 

 Following is a list of the species found in the large-it known grotto : 



Polypodium polypodioides (Eesun-ection-ferii) 



Polypodium Plumula (Polypody) 



Polypodium pectinatum 



Pteris cretica (Bracken) 



Adiantum tenerum (Maiiidenhair-feni) 



Asplenium abscissum (Spleenwort) 



Asplenium Curtissii 



Asplenium heteroehroum 



Asplenium platyneuron 



Asplenium vereeundum 



Tectaria heracleifolia (Halberd-fern) 



Dryopteris floridana (Wood-fern) 



Dryopteris normalis (Shield-fern) 



Dryopteris reptans 



These species, or the related tj'pes in the case of the endemic 

 Asplenium Curtissii, are of general tropical distribution. The plants 

 are evergreen and have no apparent resting period during the .vear. 



Such a copious growth of ferns is rarely se^n anywliere else in Flor- 

 ida. Boulders and cliffs are often entirely hidden from view b}' dense 

 masses of the various ferns growing intimately mixed. On other over- 



