l8o FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



9. At an\ time what has been regarded as a single species may be 

 divided into two or more by some taxonomist. When that is done the com- 

 ponents will often be fovmd to be confined to different regions, but even 

 if both (or all, as the case may be) grow in the same region, thus giving them 

 smaller percentages and lower places in the list than the composite species had, 

 it does not make any appreciable difference in summing up the percentages for 

 each family or other category of plants. 



PLAN OF REGIONAL DESCRIPTIONS. 



The description of each region follows as nearly as possible tlie 

 following plan : 



References to previous literature and illustrations. 



Location and area. Extent of similar country elsewhere (if any). 



Geology and Soils — Soil analyses (if any). Soil fauna or subterranean 



animals. 

 Topography and Hydrographj'. — ]\Iaximum and minimum altitudes. Springs 



arid streams, lakes and ponds. Character and fluctuation of water. 

 (Climate. See page 182.) 

 Vegetation Types. — Frequency of fire in each. 

 Field work of the writer, by months. 

 List of plants — 



Trees. 



Small trees or large shrubs. 



Woody vines. 



Shrubs. 



Herbs. • » 



Noteworthy features of the list. 



Characteristic species, etc. 



Percentage of evergreens, Ericaceae, Leguminosae, etc. 

 Economic features. 



Utilization of native plants. 



Proportion of improved land. 



Density of population. Rate of increase. Proportion of white and 

 colored. Principal crops. 

 Illustrations. 



The amount of space devoted to each topic varies with the char- 

 acter of the region, and the order is not always exactlv as given 

 above. Some of the items in the foregoing outline seem to call for 

 a little more explanation, which follows. 



Bibliographic references. A list of books and papers relating to 

 the geography of northern Florida will be found near the end of 

 this volume. (See table of contents.) At the beginning of each 

 regional description there are references to the more important or 

 easilv accessible works in the list from which additional infnrma- 



