112 



Spread. 



By virtue of the superficial strands the fungus possesses an excel- 

 lent means of propagation. A careful search has failed to demonstrate 

 the presence of any spore-bearing organs, nor were these developed 

 when the mycelium was placed in a moist chamber and kept for 

 several weeks. It may, therefore, be concluded that the primary 

 means of propagation is by the vegetative strands and that this is 

 accompanied by a suppression or partial suppression of the spore- 

 bearing organs. 



It has been possible to trace the mode in which infection occurs 

 in the field. Here and there infected leaves have been blown by wind 

 and lodged against a branch. The mycelium on the leaf accumulates 

 a dense growth by which the leaf is made to adiiere closely to the 

 branch. From this point strands arise and traverse the branch in all 

 directions. Infection was also seen to pass from a branch on an in- 

 fected tree to a healthy tree through the leaves of adjacent branches 

 being in contact with each other. Again, in the case of two camphor 

 plants, the strands were seen to pass from fallen leaves on the ground 

 up the branches and to reach the younger twigs. 



The mycelium of the fungus is very sensitive to moisture and to 

 contact. The former is illustrated by the dense growth which is ac- 

 cumulated when the mycelium is placed in a moist chamber and when 

 the mycelium reaches the more shaded and damper portions of a 

 branch. The latter is shown by the rapid growth of the mycelium 

 where two leaves or twigs come into contact with each other or where 

 an infected leaf lodges against a branch. 



Distribution. 



Judging b}' analogy with other "thread-blights" one may well 

 expect that this fungus comes m from the jungle; and the close 

 proximity of the plants hitherto attacked to the jungle is in favour of 

 this conclusion. In neither case, however, was it possible to make an 

 examination of the jungle adjacent to the infected area. 



The fungus on Hevea and the one on camphor were, as far as can 

 be ascertained by an examination of sterile mycelium, identical with 

 each other. A fungus which is similar in all respects to the one on 

 Hevea has also been found on Guava {Psidiuni Guyava). From what 

 is knov.-n of fungi of this nature it is improbable that in the jungle it 

 should confine itself to even a few different plants. 



Other Thread-Bilghts 



Several fungi of a similar nature have been described from differ- 

 ent parts of the v.orld. The best known of these is, perhaps, the 



