—3— 



investigations. This rust appears as a thick orange coating on the 

 under surface of the leaves and attains its greatest development in 

 June. 



Figure 1— Orange Bust Fungus, Cseoma nitens, 

 Schw. Cross-section of a diseased leaf; a spores; 

 6, immature spores or sterile bodies; c bed of fun- 

 gus issue; d mycelium threads; e suckers; g sper- 

 magones; h cells of leaf; m epidermis of upper leaf 

 surface. (After Burrill.) 



The leaves do not reach their full size, are unusually rigid, and have 

 a sickly appearance; something of this may be seen even before the 

 yellow coating appears, and the latter at first appears in definite and 

 ppler patches, somewhat like scales, standing out slightly on the under 

 leaf surface, covered by the epidermis, through which they afterwards 

 burst. In this early stage, on the upper surface may be seen also yel- 

 lowish specks, which on closer examination prove to be protuberances. 

 There seems to be an exudation from these, which attracts insects. 



Microscopic examination shows that the orange portion consists of a 

 great number of roundish spores. Their surface is roughened with 

 sharp points, by means of which it is possible that they adhere to 

 insects crawling over the leaf and are carried by them to other plants. 



