XXIV.] 



BARBERRY BLIGHT. 



161 



black dots ; but if we look at the JEcidiwm clusters with a 

 similar lens, \ve shall see companies of beautiful sulphury 

 yellow cups, bursting open through the lower epidermis 

 of the leaf, and each cup filled with yellow powder re- 

 sembling small pollen-grains. 



To understand the nature of the dEcidium cups and the 

 black spermogone dots, we must cut a section through the 

 barberry leaf, and this section must be so made that it 



FIG. 83. 



Section through a Barberry leaf, showing the cups of jEcidium. Berberidis, 

 Pera. , below, and the Spermogones above. Enlarged 50 diameters. 



will pass through the centres of the cups and the spermo- 

 gones. Such a section is illustrated at Fig. 83, enlarged 

 50 diameters. A represents the lower surface of the leaf, 

 and B the upper. At C one of the little ^cidia is seen 

 buried (a small chamber full of spores) in the tissues of 

 the leaf, and at DD two of the JScidium cups are seen 

 quite mature and open, the epidermis of the barberry leaf 

 M 



