666 THE AMERICAN NATURALIST [Vol. XLY 



botanized extensively in the vicinity of Albion, never 

 has encountered it. From a glance at the map it appears 

 not improbable that this plant, perhaps having its origin 

 in Massachusetts, or introduced there from Europe, 



perhaps in ballast, gradually has been transported to 

 various points of the compass, the area being covered by 

 it being limited to the northeastern section of the United 

 States. The transportation of seed, provided this is 

 formed at all, is not unlikely. Fairly large gaps, though, 

 appear between certain of the dates of collection. Thus, 

 the plant does not appear to have been collected between 

 1837 and 1858, between 1865 and 1890, between 1894 and 

 1907, gaps, respectively, of eleven, fifteen and thirteen 

 years. Yet these lacunae very well may be accounted for 

 on the one hand by the failure of botanists to collect the 



