122 -AMBRICAN FERN JouRNAL 
Mr. Christensen’s expressed belief that the species of the 
marsh fern group and those of the shield fern group real- 
ly constitute separate genera. 
Some time ago, in reviewing Dr. J. K. Small’s “Ferns 
of tropical Florida,” the present writer remarked that 
the chief regret of the fern lover who goes South would 
be that the author had not extended that work to cover 
the whole of the state. He has now done so to the 
extent of giving, in a brief article, a more or less complete 
list of the species known to occur within its boundaries 
and a general account of their habitats and distribu- 
tion.? 
In all about 90 species are mentioned, though Dr. 
Small states that more than one hundred have actually 
been found. Three, Pycnodoria (Pteris) longifolia, Dry- 
opteris setigera and Marsilea vestita, are introduced; 
seven are found only in Florida. The remainder Dr. 
Small divides into two main groups, northern species 
whose range extends from Florida northward or west- 
ward along the Gulf of Mexico, and tropical species 
which reach Florida from the south. The former com- 
prises about one third of all the species and most of those 
widely distributed within the state. The latter, though 
twice as numerous, are for the most part confined to two 
comparatively limited areas—the keys of the coast and 
the Everglades, treated in Dr. Small’s earlier work, and 
the lime-sink region in the northwestern part of the 
peninsula, which has figured in the pages of the JourR- 
NAL.* The latter is an isolated area in which the occur- 
rence of tropical ferns is not easy to explain. 
*Small, John K. The land of ferns; the habitats and distribution of 
the fernworts of Florida. Journ. Elisha Mitchell Sci, Soc. 35: 92-104 
Amer. Fern. Journ. 6: 42-44, 1916 and R. M. Harper, The Fern Grottoes 
of Citrus County, Florida, Amer. Fern. Journ. 6: 68-81, pl. 5, 1916. 
