Bui. 842, U. S. Dept. of Agriculture. 



Plate IV. 





■>'-■■ f% 



A 



Normal Kernels of Wheat with Nematode Galls and Objects 

 for which the latter have been mistaken. 



Fig. 1 (above). — A, Normal kernels of wheat; B, dark, smooth nematode galls; C, 

 black papillate seeds of cockle; D, smutted wheat grains (smut balls); and E, 

 bin-burnt kernels. Compare the sound wheat with the nematode galls and note 

 the pronounced difference between the latter and the cockle seed, smutted grains, 

 and the bin-burnt kernels for which the nematode galls are often mistaken. 

 Twice natural size. Fig. 2 (below). — A, Unstained, thick cross section of a 

 normal wheat kernel; B, cross section of a flower gall filled with a white mass of 

 nematodes, for comparison as to shape, size, and content. X 6. 



