Chapter 12. 
DISEASES OF LEAVES (contd.). 
Rusts. The Wheat Rust. Life Story of the fungus, relation to 
the Barberry. The Mint Rust and Hollyhock Rust as examples 
of other Rust diseases. 
_ The Rusts constitute a very important group of plant 
diseases, which includes some of the most widely dis- 
tributed and highly destructive of parasitic fungi. The 
grain-producing plants and grasses of our fields, the 
plants of our gardens and greenhouses, and even forest 
and fruit trees are attacked by members of the rust 
family of fungi. Of all plant diseases they are in many 
respects the most remarkable, as they are also the most 
difficult to combat. Whilst the nature and the life history 
of the fungi causing them have only been known for a 
relatively short period, the blighting effects caused by out- 
breaks of these maladies are referred to by writers of the 
remotest antiquity. Throughout the centuries wheat rusts 
have been responsible for great damage wherever wheat 
has been grown, and at the present time the loss caused 
to the wheat crop alone throughout the world amounts to 
many millions of pounds annually. 
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