Bui. 40, U. S. Dept. of Agriculture. 



Plate II. 



Fig. 1.— Malformed Mosaic Leaves of Nicotiana tabacum (A, B, C, and D) and 

 a Healthy Leaf (E). 



(Somewhat reduced.) 



Fig. 2.— Mosaic Leaves of Nicotiana tabacum, Showing the Development of 

 Prominent Blisterlike Outgrowths of the Leaf Tissues. 



These swellings appear on the upper face of the leaf and are usually very dark green in 

 color in comparison with the rest of the leaf. (Natural size.) 



