146 IN LOWER FLORIDA IVILDS 



mainland, and we get some 1500 total in an area 

 of 3000 square miles. I confess at first to sur- 

 prise at the small number of species in a region 

 of the size and lying, too, at the very door of the 

 tropics. On reflection, however, the reason is 

 easily understood. The area considered is very 

 new ; it was elevated above the sea only yesterday 

 (geologically speaking) and is scarcely dried off 

 yet. Hence there has been insufficient time to 

 accumulate an extensive flora. The sandy soil is 

 poor, and over much of the area the rocky ground 

 has no covering whatever. Lime is poison to many 

 species of plants and such will not grow in most of 

 our territory. There is but slight variation in the 

 contour of the entire region and this would pre- 

 clude the mountain species and those affecting 

 elevated or broken land. 



I have already stated that the Florida Keys are 

 being worn away and that they formerly occupied 

 a larger area than at present. Dr. Small, who 

 has made a careful study of the flora of Lower 

 Florida, believes that some species of plants which 

 formerly existed on the keys are found there no 

 longer, having inhabited land now destroyed; 

 this view is doubtless correct. 



