Index Frequency Method 



527 



J C 



' I R 



I ' I S 



8 



10 11 



12 3 4 5 6' 



Fig. 149. Histograms of Tradescantia populations of thirty plants each. 

 B, a population of T. canaliculata and F, one of T. virginiaua. A, C, R, S, 

 and Y represent six populations of hj^brid swarms. All the populations are 

 plotted by the same index-frequency method and their positions roughly 

 show their relation to one another. (From Anderson in Annals of the Mis- 

 souri Botanical Garden.) 



