94 Journal of the Mitchell Society [June 



Little is known concerning a rare bracken, Pycnadoria longifolia, 

 within our range, and it may jQi prove to be a native plant. There 

 seems to be no good reason why it should not be native, for it occurs 

 plentifully on the islands on the other side of the Gulf Stream. The 

 other exotic has found such favorable habitats and grows in such a 

 natural manner that it is difficult to realize that it is not a native 

 plant. In fact, never has a satisfactory explanation been offered as 

 to how the large wood-fern, Dryopteris setigera, did gain a foothold 

 in these apparently natural habitats. Of course, it may be that its 

 spores were primarily carried there by winds from cultivated plants 

 and thus lodged in favorable habitats. But the true manner of its 

 introduction may remain a mystery forever. The pepperwort, 

 Marsilea vestita, is native west of the Mississippi River. It seems to 

 have been brought into Florida through the agency of the railroads, 

 and as far as we know it has not been found far away from the lines of 

 traffic. 



Two additional species, a bracken, Pycnadoria cretica, and a 

 clubmoss, Lycopodium cernuum, are sometimes considered naturalized 

 plants, but there has never been good evidence advanced to support 

 that theory. 



There are seven endemic species in Florida. These are : 



Aspleiiium biscayneaiium (Spleenwort) 



Asplenium Ciirtissii 



Tectara Amesiana (Halberd-fern) 



Selaginella funiformis (Eesurrection-plaut) 



Selaginella Inimifusa 



Isoetes Chapmauii (Quilhvort) 



Isoetes alata 



The first-mentioned spleenwort grows in only one hammock — a 

 hammock on the Everglade Keys, in the southern end of the Ever- 

 glades, while the second one is found in hammocks in the lime-sink 

 region of the northern part of the peninsula. The Tectaria is known 

 only in the hammocks of the Everglade Keys. The first-cited species 

 of Selaginella occurs in peninsular Florida, while the second one has 

 been found in northern Florida, as well as in the peninsula. The 

 first-mentioned quillwort has been found only in western Florida, 

 while the second one is known to occur only in the Gulf Hammock 

 region. This region is a rather narrow strip along the upper western 

 coast of the peninsula with limestone near the surface or cropping out. 

 The coast line differs from that farther south in being devoid of 



