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the entire young fruit is involved, and it may die and fall ; but 

 more often the fruit hangs upon the tree and the diseased portion 

 becomes drj-, hard, black and sunken. Such a fruit, with the 

 entire top third deformed by rust, is shown in Fig. ii. This rust 

 fungus also penetrates the twigs, and often causes knots to ap- 

 pear, resembling the black knot of the plum (Fig, 12). This fun- 

 gus has a curious life history. Upon the quince, and some relat- 

 ed fruits, it is known as Roestelia aurantiaca, but it is really only 

 a form of another and very diflferent looking fungus which causes 

 apple-like swellings upon the twigs of red cedar trees and 

 juniper bushes. Upon these plants the fungus is known as 



10. — Rusted young quinces. The left hand specimen is attacked at the blossom- 

 end and the other at the stem end. 



Gyvinosporanghan davipes. This cedar fungus, or so-called 

 cedar-apple, produces its spores in spring, and these are carried 

 by the wind, and, alighting upon the quince, soon produce the 

 rust ; and when this rust upon the quince first attracts attention, it 

 is already beyond control, as I have said, save by removing and 

 burning the diseased parts. The spores produced by the quince 

 rust are incapable, so far as known, of again producing the rust, 

 but they are scattered by the wind and when they come upon the 

 cedar or juniper produce the cedar apple stage. It has been 



