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cies with species for light and air is so fierce that only 

 individuals specially adapted to the habitat can hope to 

 form extensive colonies. Even our cinnamon fern, which 

 inhabits almost every swamp and wet woodland in the 

 north, is reduced to a few acres in a single marsh in 

 Jamaica. In the tropics many ferns are obliged to grow 

 upon other ferns, or on the branches of trees, to find 

 room for existence, fitting themselves into any vacancy 

 as best they can. The behavior of the common gray 

 polypody or resurrection fern, so common on the live 

 oaks about New Orleans, is an illustration of this. In the 

 northern part of its range it grows on the earth or on 

 rocks ; hereabouts it is usually an epiphyte. 



Thus it happens that while southern ferns are more 

 abundant as to species, and, taken plant for plant, are 

 more abundant as to individuals, a single species rarely 

 becomes conspicuous because of its numbers. It may 

 grow in one restricted spot and not be found again in the 

 same country. In Jamaica the rattlesnake fern is con- 

 fined to a few acres of woodland, while the representative 

 of the common grape fern, Botrychium Jenmani, is found 

 on a single scrubby hillside. One might search the island 

 for years without finding either. Owing to this isolation 

 of species, southern regions must be examined more care- 

 fully than others before their species are all catalogued. 

 This doubtless explains Mr. Eaton's recent successful 

 trip to southern Florida, which added half a dozen or 

 more species to the fern list of the United States. The 

 performance might possibly be repeated again with equal 

 success by varying the route a bit. 



Again, the Southern States are most advantageously 

 situated for obtaining additional species of ferns from 

 other regions. At least 75 per cent, of Florida's ferns are 

 species whose centers of distribution are in the West 

 Indies or further south. And if we divide the State into 

 the northern and southern half, the percentage of tropi- 

 cal ferns in the southern half rises to more than 90 per 

 cent. Whether these species were derived from the West 



