102 JOURNAL OF THE MITCHELL SOCIETY [June 
Okeechobee. Here vegetation is protected by the tempering of the 
westerly winds, that blow across the lake in winter. Asa 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 (Morus), sweet-gum (Liqui- 
dambar), ash-leaved maple (Negundo), maple (Acer), and flowering 
dogwood (Cynozylon). The boulders, sinks, chasms, cafions, 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 (Polypodium polypodioides) is the only truly epiphytic kind. 
Following is a list of the species found in the largest known grotto: 
Polypodium polypodioides (Resurrection-fern) 
Polypodium Plumula (Polypody) 
Polypodium pectinatum 
Pteris cretica (Bracken) 
Adiantum tenerum (Maindenhair-fern) 
Asplenium abscissum (Spleenwort) 
Asplenium Curtissii 
Asplenium heterochroum 
Asplenium platyneuron 
splenium verecundum 
Tectaria heracleifolia (Halberd-fern) 
Dryopteris floridana (Wood-fern). 
Dryopteris normalis (Shield-fern) 
Dryopteris reptans 
These species, or the related types 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 year. 
Such a copious growth of ferns is rarely seen anywhere else in Flor- 
ida. Boulders and cliffs are often entirely hidden from view by dense 
masses of the various ferns growing intimately mixed. On other over- 
