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THE AMERICAN NATURALIST [Vol. XLIII 



and sources of error are so numerous that great stress is 

 not to be laid upon the results of the examination of a 

 single series of material, but all conclusions must be 

 tested repeatedly and on widely dissimilar organisms. 

 The present lot of broom deserves consideration in this 

 connection. 



Cytisus is a native of Europe which has been reported 

 from several localities in the United States. Mr. Vinal 

 N. Edwards writes me that he started the colony from 

 which my collection was taken in 1887 when he set out 

 forty small plants which he dug up on Naushorn Island. 

 In 1898 it was all cut down level with the ground when it 

 came up thicker than ever. He thinks it was first planted 

 on Naushorn Island some fifty years ago. 



It seems hardly worth while to look farther for the 

 ultimate origin of the colony since we have only a single 

 series of European data for comparison. Several years 

 ago Pearson collected ten pods each from a series of 120 

 plants at Danby Dale. To render his series readily com- 

 parable with my own I have multiplied his frequencies by 



Table I 



