64 



This is I think, very doubtful. Trees shown to me as Daru in 

 Sumatra were certainly not of this species. Probably more than 

 one plant is the source of the timbers known as Daru in the trade . 

 Most of it now I believe, comes from Sumatra. 



H. N. R. 



A FUNGUS ATTACKING ROOTS OP 

 PARA RUBBER. 



From two Estates I have received rubber stems attacked with a 

 subterranean fungus which does not appear to be Fomes semitostus. 

 The trees are all young about 2 inches through. The roots are all 

 encrusted with a white mycelium and dead, and the collar of the 

 tree is also dead. One planter from Borneo writes that " If left alone 

 the trees are absolutely dead within three weeks of the first appear- 

 ance of the disease. They rot at the roots and in the green wood. 

 The inside of the stem becomes discoloured and the tree falls. 

 From 70 to 80 of the trees have died. They were not growing in a 

 batch but are scattered about amongst the healthy trees." The 

 other planter sends somewhat similar information from Perak. The 

 disease appears sporadically there also "The trees were growing" he 

 writes "most luxuriantly on a new field, 8,000 of them, yet here and 

 there wide apart about a dozen died. " The trees are I gather about 

 16 months old. 



It is impossible as yet to guess that fungus is the aggressor, as 

 there are no sporophores yet. The stumps are put in a damp spot 

 to see if the fungus will fruit. It is doubtless I think, one of the 

 Polyporeae. I have seen a very similar attack on Clove trees in 

 Malacca. The trees appeared healthy but died suddenly, retaining 

 their leaves. The death was attributed to Termites, but on digging 

 up the trees the roots and up to the collar of the tree was found to 

 be coated with Mycelium in the same way as the Para rubber trees 

 are. Another fungus if not perhaps the same thing, was well known 

 to serve Coffee bushes in the same way. This proved to be Irpex 

 flava, a yellow Polyporus, which I have seen attacking other trees 

 ground infested by this plant was considered unfit for planting on, 

 and in the days of Coffee one often saw little spots of ground 

 where it was said Coffee would not grow, and this was due to the 

 Mycelium of the Irpex. It did not seem to spread however, and 

 often occupied an area a few feet square only. 



The Malays had a theory that this death of trees on special bits 

 of ground, was due to a trunk of a poisonous tree lying buried 

 beneath the ground, and in a sense they were not far wide of the 

 mark. Irpex like all this class of fungi is naturally a saprophyte 

 living on dead timber but under certain circumstances not very 

 clear becomes parasitic attacking living wood, and it is probable 

 that the roots of the trees infected reached a mass of under 

 ground decomposed wood infected with Irpex. Probably something 

 of this kind has gone on in these estates where the Rubber trees 



