214 Some Diseases of Plantation Rubber in Malaya 



obtaining a spore deposit, for even when sections showed that spore- 

 producing basidia were present their number was very small. In view 

 of the apparent paucity of spore production it would be interesting 

 to have fuller information concerning the manner in which the fungus 

 first begins to spread in a young rubber plantation. 



3. Polyjjorus rugulosus, Lev. 



On several occasions another polyporoid fungus was seen growing 

 at the collar or upon exposed lateral roots of diseased rubber trees 

 and it seemed likely that this fungus was the cause of the disease from 

 which the trees suffered, although inoculation experiments are needed 

 to settle this point definitely. The tissues of the host near the fructifica- 

 tions were invariably decayed, the foliage of the affected trees became 

 thin, and the branches died back after the manner of trees attacked 

 by a slowly growing root parasite. I saw this disease only in trees 

 which were in tapping and it appeared to be more frequent in badly- 

 drained low-lying estates than upon undulating land. One tree severely 

 attacked by this fungus had been previously invaded by white ants. 



The fructifications of this fungus are often densely imbricate and, 

 in the aggregate, form large masses several inches across although 

 a single pileus is only an inch or two in diameter. The upper surface 

 is smooth, brownish, and zoned ; the under pore-bearing surface is 

 white when young, becoming yellowish brown with age; the pores are 

 minute; the substance of the fructification is thin and although fleshy 

 when young is leathery at maturity. Both in the colour of the pores 

 and in the much thinner substance the fructifications of this fungus 

 differ markedly from Fomes lignosus. 



I am indebted to Miss Wakefield of the Royal Botanic Gardens, Krw . 

 for kindly identifying this fungus as the Polyporus rugulosus of Leveille. 

 The type specimen of this fungus was obtained from tree trunks in 

 Java and was described by Leveille in 1844. Saccardo(i7) has since 

 placed the fungus in the genus Fomes, but on account of the texture 

 of the fungus when young it is preferable to retain the original uame. 

 I have been unable to find any previous record of this fungus upon 

 rubber trees. 



Pending a further investigation of this fungus, rubber trees affected 

 by it should be treated as for Fomes lignosus. 



