Disease of Rubber caused by Ustulina Zonata. 155 
Description of the Fungus. 
In Malaya the fruit-bodies of the fungus arise as small greyish 
brown plates on the exposed lateral roots or collar of the affected 
tree, the growing margin of the fructifications being usually greenish 
in colour. Petch (4) describes the occurrence of a conidial stage 
when the fruit-body is young in which condition the surface is 
covered with a white felt consisting of slender, closely packed 
Fig. 3. Ustulina zonata. Photograph of the lower part of a diseased 
rubber tree bearing a fructification of U. zonata (F). The tree has been opened 
up to shew the limits of diseased and healthy tissues (D and H respectively) 
above the collar. Latex (L) has exuded where healthy bark has been cut. 
conidiophores which abst'rict small, hyaline spores from their 
extremities. 1 have not found this conidial stage on young fructi¬ 
fications kept under observation in Malaya, though it may be 
subsequently found. Mr. T. Petch has, however, kindly sent me 
some specimens in the conidial condition taken from a Mango tree 
in Ceylon, from which Fig. 4, A, has been drawn. The conidia are 
about 4[a x 2 /a in size. These fructifications in the conidial stage 
from Ceylon are much lighter in colour than the fructifications 
devoid of conidia of about the same age obtained in the Federated 
Malay States. Adult fruit-bodies gathered in Malaya have been 
compared with mature specimens of Ustulina zonata from Ceylon 
and other countries, in the herbaria at Kew, and at Peradeniya, 
with which they are undoubtedly identical, hence there is no 
hesitation in naming the fungus Ustulina zonata (Lev.) Sacc. 
