148 DISEASES OF FIELD & GARDEN CROPS. [CH. 



Uredo in the black spots in the bottom left-hand corner 

 of the illustration. Two pustules (technically sori, or 

 spore cases), are further enlarged to twenty-five diameters 

 in Fig. 73. It will now be instructive to turn to Figs. 

 62 and 63, where the spring rust is illustrated to the 

 same scale. , 



X-2S- 



FIG. 73. Pustules or Sori of 

 Uredo linearis, Pers. Enlarged 

 25 diameters. 



X-3- 



FIG. 72. Fragment of Wheat leaf in- 

 vaded "by Uredo linearis, Pers. 

 Enlarged 3 diameters. 



Neither Uredo Rubigo-vera, D.C., or U. linearis, Pers., 

 are confined to one side of the foliage of cereals ; they 

 grow on both sides, and (especially in U. linearis, Pers.) 

 attack the inflorescence with its glumes and pales. The 

 latter organs have been described under ear-cockle. 



The Uredo of summer rust is less livid or yellow and 

 more orange or brown in colour than the Uredo of spring 

 rust, and being altogether larger and more robust in 

 growth it splits and lacerates the cuticle of the affected 

 plant more completely ; but the description of the pustules 

 of spring rust apply generally to the larger sori of the rust 

 of summer. 



