HABIT OF HEMILEIA YASTATRIX. 



513 





papillae. The latter are elongate and peltate, and much more 

 minute than the normal spore. 



When describing the character of the mycelium inside the 

 tissue of the leaf, Mr. Abbay mentions that a dark body is seen 

 immediately beneath each of the clusters of sporanges, and that 

 from these bodies a branching mycelium, more or less charged 

 with reddish-brown granular matter, ramifies amongst the cells 

 of the leaf. Of the exact nature of these dark bodies, Mr. Abbay 

 is unable to speak with accuracy. On a careful examination of a 

 section taken through a stomate, the dark body is found to occupy 

 the air-cavity immediately beneath ; and when soaked for some 

 time and subjected to slight pressure, instead of being " sacs of the 

 shape and size of the air-cavity," these bodies are found to be 

 composed of a number of densely interwoven threads, which are 

 continuous with those permeating the tissues of the leaf, and 

 directly connected with the fine tufts of threads which push their 

 way through the mouth of the stomate and bear the cluster 

 of orange-coloured sporanges. A figure of the complete plant 

 of the Hemileia is given in the 

 accompanying woodcut. 



In Mr. Abbay' s paper little is 

 said about the presence of the 

 mycelium outside the coffee-leaf. 

 During several months of the year, 

 w r hen the disease was supposed to 

 be absent from the coffee-estates, it 

 exists as filamentous threads, pro- 

 duced by the germinating spores, 

 and covering the bark and leaves 

 of the coffee-tree. In districts 

 affected by the south-west monsoon 

 these filaments are so abundan 

 during the months of February, M rch, and April, that it is im- 

 possible to gather a single well-matured coffee-leaf entirely free 

 from them. During the prevalence of wet weather the filaments 

 do not appear to enter the stomata, but continue to remain as ex- 

 ternal growths. In this stage Mr. Abbay describes them as pro- 

 ducing the conidioid form of fruit ; but during several months' 

 continuous observation upon coffee-estates I have not observed a 

 single instance of conidia being produced by the filaments while 

 on the coffee-leaf. They, however, appear frequently when the 



Cluster of sporanges arising from 

 a mass of interwoven mycelial 

 threads, as described in the text. 



Magnified. 



