123 



my experience over much territory and many years I have seen 

 countless plants, for example, of A. novae-angliae grow with A. 

 ericoides, yet have very seldom met with A. amethystinus evi- 

 dently a hybrid of these two.^^ Mr. Monroe was chary of declar- 

 ing hybridism; he rather considered the influences of environ- 

 mental factors in working with difficult specimens. 



When a series of diverging specimens in a species is arranged 

 from one extreme to another the gradations become apparent, 

 acting to deter workers from announcing a multiplicity of 

 varieties and forms to which they might well be tempted if 

 intermediate patterns were missing. 



Special thanks are owing Curator Albert M. Fuller of the 

 Department of Botany, through whose kindness every facility 

 of the Milwaukee Public Museum was placed at my disposal. 



Chicago, III. 



" Benke, Rhodora 32: 1-2 (1930). 



