GEOGRAIMIV AM) XKGICTATIOX OF XORTIIERX FLORIDA. 185. 



pine forest long enough hardwood trees of various kinds would 

 come in and choke out the pine (which does not thrive in shade), 

 and tlius convert the pine forest into a hammock.* Most of our 

 hammocks are in situations protected from fire b>- the topography, 

 as on slopes down which fire would not travel readily, or in places 

 partly surrounded by water. 



Besides the native vegetation every region has areas greatly 

 modified h\ civilization, such as cultivated fields, old fields, road- 

 sides, railroad rights-of-way, etc. Some of the plants in such 

 places are native species which have survived the changed C()ndi- 

 tions, but most of them have been brought in unintenti(jnally by 

 man or domestic animals from other parts of the country or from 

 foreign countries. Most of the foreign weeds in Florida seem 

 to be of tropical origin, but we also have quite a numlier from 

 Europe and Asia.f The great majority of them are herbs. 



Plants which exist only in cultivation are not here regarded as 

 vegetation. 



Plant lists. Each list aims to include all the wild plants, both 

 native and introduced, seen by the w^riter in the region under con- 

 sideration, except the rarer ones. Trees and shrubs seen onl}- once 

 or twice in a given region are usually omitted, except in the case of 

 some of the smallest regions. A much larger proportion of the 

 herbs is omitted, partly to save space, and partly because the names 

 of the rarer herbs would be meaningless to the average reader. For 

 some of the larg'er regions no herb is mentioned which has been 

 seen less than fi^'e or six times, which involves the omission of over 

 a hundred species from such a list. (For there are exery where 

 more rare species than common ones.) Such omissions however 

 have little effect on the conclusions drawn from the quantitative 

 analyses, for the percentages of the omitted species are vtvy small 

 fractions. 



*This was pointed out a quarter of a century ago by the late Mrs. Ellen 

 Call Long, of Tallahassee, but her views never gained much credence in the 

 North, where forest conditions are very different. The matter has been further 

 discussed by the writer in Bull. Torrey Bot. Club 38:515-525- iQH: 4T -^U- iQU; 

 Geol. Surv. Ala. Monog. 8:25-26. 83, 116. 1913. Pop. Sci. Monthly. 85:353-354. 

 1914. (See also C. D. Howe in Forestry Quarterly. 11 :545-546. Dec. 1913^- 



tFor notes on Florida weeds see tlie paper by Neal cited in the bibliography, 

 .-mrl for sneculations on <-V;c origin of some of our weeds see Bull. Torrey 

 Bot. Cluli 3S :34r-3''^o. 1908. 



