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NATURALIST'S GUIDE TO THE AMERICAS 



Florida. The extreme southern part 

 of the peninsula is practically tropical. 

 The infrequent frosts are so light that 

 they do not ordinarily penetrate the 

 forest canopy, with the results that 

 tropical plants can grow as undergrowth. 

 This region is, however, very narrow, 

 extending but a few miles from the coast, 

 and gradually changing as it goes north. 

 Probably St. Lucie Inlet should be 

 considered as about the northern limit 

 of the subtropical temperatures. On 

 the west coast it extends up to about 

 Fort Myers. 



3. Soils 



The soils of the state are mostly sandy, 

 and in general progressively lighter from 

 north to south and towards the coasts. 

 Over much of the state, especially the 

 interior, the sand is underlaid at no 

 great depth by strata of clay or lime- 

 stone. In places along the northern 

 edge of the state, as about Marianna, 

 Tallahassee, Monticello and Madison, 

 a rather sandy red clay outcrops. Many 

 swamps have a layer of muck on the 

 bottom. These, when drained, ulti- 

 mately make rich trucking lands, con- 

 sequently there are many drainage 

 projects. The largest of them is the 

 Everglades. 



4. Original biota 



The state's ecological youth is shown 

 by the small proportion in which the 

 native vegetation has reached the 

 climax formation, the magnolia-bay- 

 holly forest or even the present hard- 

 wood forest or "hammock," which is 

 largely made up of deciduous trees, 

 and by the general small amount of 

 humus in the soil. Ecological suc- 

 cession is slow. The natural deposition 

 of humus is slow, even when not inter- 

 fered with by man. The high mean 

 temperature causes rapid nitrification 

 and the torrential rains of summer wash 

 the nitrates from the soil into the 

 streams which are dark with organic 

 matter. But fires are very common 



during the dry season with the result 

 that most pine- and grass-covered lands 

 are burned over every year or two and 

 ecological succession prevented or 

 reversed. 



To understand the types of vegetation 

 in Florida it is important that one 

 should bear in mind that there is a 

 marked dry and wet season. The wet 

 season occurs generally during the 

 months from June to September (Octo- 

 ber on the East Coast) ; the drier season 

 from November to May, usually reach- 

 ing its climax in April. This diversi- 

 fication of seasons becomes more marked 

 the farther south one goes in the penin- 

 sula. It is the inability to withstand 

 the dry season which retards the spread 

 of the hammocks and limits them to the 

 more moist soils or to those that best 

 retain water. It also explains why 

 many plants such as red maple, ash, 

 hackberry, and blackberries, which 

 grow in mesophytic situations in the 

 north are in Florida confined to swamps 

 or moist soils. 



We can divide the vegetation of 

 Florida into five great groups: 



1. Grassy Swamps, Savannas, and 

 salt marshes, of which the Everglades 

 would be the largest example, areas 

 largely under shallow water during the 

 summer, and comparatively dry during 

 the winter and spring and covered with 

 a growth of very tall grasses and sedges, 

 one of the most common being "saw 

 grass," (Cladium effusum), a sedge. 

 On the higher points and islands are 

 occasional patches of forest. Border- 

 ing these islands and swamps is often a 

 narrow zone occupied by a more or less 

 dense grove of cabbage palmettoes whose 

 tall, slender, naked trunks, bearing at 

 the top a cluster of large leaves, give 

 to the landscape of much of Florida its 

 tropical appearance. On the other 

 side these savannas merge into the 

 aquatic vegetation of the lakes and 

 swamps (and along the coast salt 

 marshes), such as water lilies, and 

 especially the floating water hyacinth 

 (Piaropus crassipes), which almost cov- 



