PLATE XLVIII 



Contact infection. A part of the new tubers becoming infected with Spondylocla- 

 dium atrovirens by means of contact with the infected mother tuber. In this case it 

 is a distinctly stem-end infection. Harvested on September 19, 1915, at Presque 

 Isle, Me. 



37767°— iG 2 



