Native 



Native and 

 Introduced 



30 



29.6 

 28.4 





34-9 





29.4 

 28.5 



20!) 



Altamaha (irit region of Georgia (Harper, 1906), 

 Florida (Hitchcock, 1899-1901), 

 Lee County, Florida ( Hitclicocl<, 1902), 

 Plaquemines Parisli, Louisiana (Langlois, 1881), 

 Losver Louisiana (Langlois, 1887), 



It is rather unfortunate that local floras of parts of Eastern 

 North America which include neither coastal plain nor glacial 

 drift are not numerous. There is not yet even one for the 

 southern AUeghanies from which any such calculations as these 

 can be made. The following regions, however, include none of 

 the Pleistocene areas above mentioned, or such a small proportion 

 of them that it does not seriously impair the results. 



Chester County, Pennsylvania (Darlington, 1853), 



West Virginia (Millspaugh, 1892), 



West Virginia (Millspaugh & Nuttall, 1S96), 



Tennessee (Gattinger, 1901) 



Jackson County, Missouri (Mackenzie & Bush, 1902), 



Athens and vicinity. Middle Georgia (Harper, I900), 



Metamorphic region of Alabama (Earle, 1902), 



In this list some of the percentages which are higher than the 

 averages are capable of explanation. In Chester County, Penn- 

 sylvania, Muhlenberg's work on the grasses and sedges of the 

 vicinity early in the century may have had something to do with 

 the relatively high proportion of monocotyledons recorded. 

 And in Earle's Flora of the Metamorphic Region of Alabama 

 the southern boundary of the region is so loosely drawn (as the 

 author admits in his preface) that a considerable coastal plain 

 element is included. 



The discrepancies between different figures in any one of these 

 three lists may be due as much to personal equation as anything 

 else, and it is remarkable that they are not greater. But with all 

 sources of error included, the above statistics nevertheless seem 

 to show that no glaciated or coastal plain area contains less than 

 30 per cent, of native monocotyledons, while none of the older 

 regions has more than 27 per cent. If authors of future local 

 floras will bear this method in mind and tabulate their species 



Native 



Native and 

 Introduced 



27 

 21.8 



25-7 

 20.6 





20.7 





24 



19.8 

 26.7 



27 

 25.6 



