1 1 6 British Urcdiiicce and Ustilaginea:. 



with them ; then, by simply brushing the water on the 

 leaves, you may be pretty sure of successfully infecting 

 the plant. Replace the bell-glass, and give it another 

 douching outside with the watering-can. If sufficient 

 material has been prepared, each alternate barberry may 

 be infected in the same manner. The bell-glass need 

 not be kept over the infected plants more than two or 

 three days. If the weather be very bright, the bell-glasses 

 should be shaded by putting a piece of matting or carpet 

 over them to prevent the foliage being scorched by the sun. 

 In the course of eight or ten days the yellow spots on 

 which the spermogonia are produced will appear, and in 

 two or three weeks the perfect secidiospores will be de- 

 veloped. It will then be seen that only those barberries to 

 which the spores were applied have the aecidiospores on 

 them, while the alternate plants remain free. If an attempt 

 be made to infect a plant in the day-time, when the sun's 

 rays are full upon it, it will be found that the water all 

 runs off the leaves ; but by operating in the evening in the 

 manner directed, the leaves are bedewed with a thin layer 

 of moisture, and no difficulty will be found in applying the 

 spore-charged water. 



Should it be desired to perform the converse culture — 

 the infection of wheat plants with the barberry aecidiospores 

 — greater care is necessary to prevent the control plants from 

 becoming infected, because the aecidiospores will not diffuse 

 themselves in water, and are very readily carried away by 

 currents of air. The simplest way is to plant some wheat 

 in two flower-pots, and at once to place the pots on two 

 plates of water and cover each with a bell-glass. As soon 

 as the young wheat plants have made a green leaf, those in 

 one of the flower-pots may be infected, using the same 

 precautions as are given above. The aecidiospores may be 

 collected by brushing them into a watch-glass of water 



