128 



24. Specimens of leaves, roots, stems, etc., were taken from 

 diseased trees for microscopic examination and whereas the roots 

 and stems appeared to be quite normal, the leaves were in a 

 diseased condition. By cutting a transverse section through a 

 diseased spot while still yellow, there could be noticed, by careful 

 staining, a delicate, septate branched mycelium occupying the 

 intercellular spaces and running between the cells. These even- 

 tually become pushed apart from one another by the invasion of 

 this mycelium, from which minute branch-like structures are sent 

 off into the cells themselves. They may possibly act as haustoria 

 or sucking organs. Finally these branches appear to grow and 

 eventually the cells and vessels of the leaf become invaded with 

 mycelium, which probably causes the death of the invaded patches. 

 The margin of the diseased spot is characterized by a ring of 

 dark colour, and examination shows that here the mycelium of 

 the fungus is only intercellular and that the filaments end in this 

 dark margin. This shows the leaf is responding to the unnatural 

 irritation caused by the invasion of the fungus and is probably 

 secreting some substance with which to protect itself. Such an 

 observation as this would suggest that the fungus mycelium is 

 parasitic in nature and was capable of producing the death of the 

 leaves. 



When the diseased spot becomes grey and dry, the minute warts 

 on their upper surfaces begin to make their appearance. These 

 small pustules bear the spores of the fungus. 



25. The infection experiments leave no doubt that this leaf 

 fungus is parasitic and show that infection can take place by the 

 germination of the spores, the germinal tubes of which can pass 

 through the stomata of the leaf, and through wounds of any kind 

 on the leaf surface. No result, however, was obtained when the 

 spores were placed on the upper surface of an uninjured leaf, 

 which therefore shows that these germinal tubes are incapable of 

 penetrating through the epidermis of the leaf. 



26. Recently, a report on a disease of coco-nuts caused by 

 Pestalozzia palmarum, Cke. by Dr. Charles Bernard has come to 

 hand from Java. Differences occur in the description of the 

 disease from Cuba (West Indian Bulletin Vol. vi, p. 313) and that 

 from Java. In Cuba, the fruiting bodies of the fungus are 

 described as being emitted from the under surfaces of the leaves, 

 whereas in Java the fortifications occur on the upper surface only. 

 The distribution of the disease in Java appears to be limited 

 to you g plants and seems to do the most damage when 

 the young plants are beginning to take root in the ground, after 

 they have exhausted most of the stored material from the 

 endosperm of the seed. 



Despite certain differences in the appearance and size of the 

 spores of the fungus found in Trinidad and that described from 

 Java, the germination of the spores appears to be similar, and 

 many symptoms of the disease in Trinidad are identical with those 

 described in Java. 

 < I am of the opinion that the Trinidad and Java fungi aie 



