MICROSCOPE AND AGRICULTURE 



and darker till it has become almost black. The 

 microscope will show us that the structure of the 

 spores has altered considerably. There is still the 

 same bunch of stalks but they have lengthened 

 somewhat and now each spore which terminates 

 each stalk is divided into two parts by a wall across 

 its narrow part. The walls surrounding the spores 

 also appear thicker, as indeed they are. These are 

 the winter spores, they fall to the ground eventually 

 and there they remain, unharmed by frost or snow 

 or rain, till the spring. In the spring they ger- 

 minate and give rise, not immediately to another 

 fungus, as might be expected, but to another kind 

 of spore. Curiously enough these new spring-formed 

 spores cannot grow upon wheat and unless they are 

 carried by wind or some other agency to a barberry 

 plant their existence is ended. Should they reach 

 a barberry leaf, however, they will germinate, pene- 

 trate the leaf and grow for a period. Eventually 

 the fungus appears on the lower surface of the leaf 

 in beautiful structures called cluster cups. Under 

 the microscope, one of these cluster cups forms a 

 lovely object. The leaf skin is split and below the 

 ruptured skin may be seen a flask-shaped hollow 

 filled with chains of minute golden-yellow spores. 

 The spores break away, one by one and favoured 

 by fortune, are carried to a wheat plant where they 

 germinate and give rise to the familiar rust. Any 

 microscopist anxious for research has a life's work 

 before him in tracing the histories of this one class 

 of fungi, should he feel inclined to shoulder the 



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