458 Eaton : Pteridophytes observed in Florida 



forest. They are numerous and botanically are the most inter- 

 esting regions. The largest, Breckell hammock, near Miami, is 

 some three miles long and half a mile wide. 



Often there is no apparent reason for the existence of these angi- 

 ospermous areas in the midst of the pine forest ; but in general the 

 requisite condition is probably a porosity of the underlying rock, 

 since the surface is usually more uneven as one approaches, and the 

 hammocks are well supplied with sink-holes from 3 or 4 to 1 2 

 feet deep and of all diameters from a few inches up to many feet. 

 The margins of these cavities are usually covered for some feet 

 down with a fern flora characteristic of limestone regions and the 

 trees and humus-covered rocks also bear a rich fern flora. A 

 striking peculiarity of the region is that one hammock may bear 

 an abundance of one species which may be absent from a neigh- 

 boring hammock of apparently the same constitution. The sur- 

 rounding pine-lands are almost free from sinks ; but such sinks as 

 do occur, and especially if holding water or if very damp, are 

 often the site of Odonto sarin clavata. Both the ferns and the other 

 interesting herbaceous plants of the Homestead hammocks, as 

 well as of those near Miami, will soon be only a memory, for the 

 hammocks are already in process of destruction. 



Of the hammocks mentioned in the list, Snapper is about 10 

 miles south of Miami. By far the most interesting are the ham- 

 mocks in the Homestead region, near the new station of Gossman's 

 on the extension of the Florida East Coast Railway ; viz., Col- 

 weirs, Costello's, Ross's, Timb's and Bauer's, as they are called 

 from the owners or nearest inhabitants. The southern portion of 

 Key Largo is very low and much of it is subject to inundation by 

 salt water. The rock is bare of humus and ferns are rare. The 

 only species I saw at Planter and Newport were Polypodium poly- 

 podioides and Campyloncurum Phyllitidis. Phymatodes exigmun has 

 also been found near the northern end of the island, but I did not visit 



* 



that part. Conditions at Madeira are similar, but a marly sediment 

 is substituted for coral. The region has been abandoned by all 

 inhabitants because of frequent inundation by salt water. No 

 new ferns were found there. 



The conditions on the west coast of Florida are entirely differ- 

 ent. The Ten Thousand Islands are mostly mangrove-covered 



