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TEXT-BOOK OF FUNGI 

 Uredineae 



Obligate parasites on higher plants, developing most 

 frequently on the leaves, but (often occurring on all growing 

 parts of the plant, and in many instances causing con- 

 siderable distortion of the part attacked. The mycelium 



FIG. 91. Urornyces colchici. i, portion of a diseased 

 Colchicum leaf: the sori are sometimes arranged in 

 irregular circles ; 2, two teleutospores, showing the 

 single germ-pore at the apex : one has germinated and 

 produced a promycelium tube bearing three secondary 

 spores near the apex. Fig. i, nat. size ; remainder highly 

 mag. 



is intercellular, giving off certain branches or haustoria, 

 which enter the cells for the purpose of obtaining food. 

 In many species the mycelium is localised or confined to 

 a limited area. After infection the mycelium produced 

 extends for a limited distance centrifugally, hence in many 

 species the particular form of fruit produced is arranged in 



