336 HARPER 



In the Leguminosa? there are 10 purple flowers, 9 cream, 8 

 blue, 7 yellow, and 4 or 5 of other colors. For dissemination, 

 in 9 species, if not more, the seeds are ejected by the sudden 

 twisting of the valves of the legume as it splits open; 7 species 

 have barbed fruits, 4 or 5 are tumbleweeds, and 2 (Kuhnistera 

 and Cercis) probably have their legumes transported mainly 

 by the wind. 



The grasses and sedges seem to be all anemophilous, with the 

 possible exception of the genus Dichromena. For dissemination 

 the perigynia of most species of Carex seem to be adapted for 

 floating and the barbed achenes of Rhynchospora and the re- 

 flexed spikelets of Cyperus retrojractus for attachment to animals. 

 Among the grasses the seeds of a few species are carried by ani- 

 mals on their fur and a few more by the wind, but in most 

 species the exact mode of dissemination is still unknown. 



Geographical Affinities of the Flora. 



Viewed as a whole, the ranges of the plants under discussion 

 show in general a striking correspondence with the geological 

 divisions of the continent as outlined near the beginning of this 

 work. The following statistics are based on those native species 

 whose ranges are pretty well known, only about 700 in number ; 

 but it is not likely that the percentages given here will be materi- 

 ally altered by future researches, for the finding of more species 

 of restricted range in the region hereafter will doubtless be to a 

 considerable extent counterbalanced by the extension at the 

 same time of the known ranges of species already reported 

 from the region. 



About 60% of the species studied are confined to the coastal 

 plain, or essentially so. Most of these (33% of the whole) are 

 confined to the pine-barrens or lower three-fourths of the coastal 

 plain (disregarding for the time being the extension of a few of 

 them into the tropics). The majority of these endemic pine- 

 barren species (nearly 17% of the total) are not known in 

 Georgia farther inland than the Altamaha Grit escarpment. 

 Accurate information as to their inland limits in the Carolinas, 

 where no Altamaha Grit is known, is greatly to be desired. 



Of the 40% not confined to the coastal plain, 31% (of the 

 whole 700) grow almost anywhere in the Piedmont region of 



