ALTAMAHA GRIT REGION OF GEORGIA 131 



States, the ranges in which are probably based on more copious 

 material than those in Dr. Mohr's great work. Several other 

 publications of more limited scope have been freely consulted, 

 and their titles will be found in the bibliography. The ranges 

 indicated in manuals and monographs are of course chiefly com- 

 piled from herbarium specimens, which are too often insuf- 

 ficiently labeled or otherwise unsatisfactory. More accurate 

 results can be obtained by consulting a number of reliable local 

 floras. This I have done in some cases, but it is too laborious 

 a task to be followed consistently throughout. One of the 

 greatest desiderata in systematic botany at present is the 

 accurate determination of ranges, 1 and this catalogue it is 

 hoped will be a slight contribution toward that end. 



The advisability of mentioning ranges at all in a local flora 

 may well be questioned by some. For no two authorities agree 

 as to the ranges of many species, and any range even when 

 apparently well known is liable to need revision by reason of 

 errors in determination of some of the material, or changes in 

 accepted specific limits, or more commonly for extensions of 

 known range by discovery. 2 And if geographical variation of 

 species was the rule, rather than the exception, it might be argued 

 that no plants outside our territory should be considered abso- 

 lutely indentical with those within. But fortunately most species 

 do not vary perceptibly from one place to another, so range often 

 becomes an important character of a species. So on the whole 

 it seems best to attempt to give the known range of each as 

 accurately as possible, in order to show the affinities of our flora 

 with that of other parts of the country. As most if not all of 

 the species have come into the region from elsewhere since 

 Pleistocene times, it becomes a matter of considerable interest to 

 study their origin, and some facts of this kind have already been 

 brought out in the summaries of the foregoing habitat lists. 



1 See Robinson, Science, II. 14: 472-473. 1901. 



2 Some botanists have even gone so far as to print ranges on herbarium 

 labels, but this practice is scarcely to be recommended, for range is a 

 property of the species and not of the individual, and if a specimen so 

 labeled turns out to have been erroneously identified the range assigned 

 to it loses its meaning. 



