(215) 
HEART EOT OF PTJ^BOXYLON UTILE (SNEEZE WOOD) 
CAUSED BY FOMES BJMOSUS (BERK). 
By Paul A. van dee, Bijl, D.Sc, F.L.S., Mycolog-ist, Department of 
Agriculture, Union of South Africa. 
(With Plates XXXIX-XLIV.) 
Table of Contents. 
PAGE 
Introduction . . . . . . . .215 
Distribution of Fomes rimosus ...... 217 
General account of the disease .... . 217 
Action of the fungus on the wood . . . 219 
Mycelium of the fungus in the host .... 220 
Description of the fungus . . 221 
Control of heart-rot caused by Fomes rimosus - - , . 222 
Summary ..... 224 
Acknowledgments ..... . . 224 
Explanation of illustrations ...... 226 
Inteodtjction. 
Ptseroxylon utile (Eng., Sneezewood ; Dutch, Nieshout ; Kafir, Um-tati) 
is a tree which appears to have but few enemies. Sim* writes : " It is 
strange that a timber so durable when dead and dry should be, while alive, 
subject to attack by a Polyporus, which not only acts on the sapwood, but is 
even more partial to the heartwood, and in many cases trees are found to 
consist of only a cylindrical shell, the centre being completely gone ; but 
even in such cases the timber, when once dead, is everlasting and proof 
against fungus and white ants. Two borers occasionally affect the tree, the 
smaller acting only in the sapwood and forming numerous small channels, 
while the larger bores through the heart wood, leaving one tunnel J in. 
diameter." The Polyporus, mentioned by Sim, is evidently Fomes rimosus, 
Berk., the fungus treated in this article. 
On the timber of this tree Simf remarks : " The timber is one of the 
hardest and heaviest in the Colony ; it is dense and close-grained, strong and 
tough, and heavily charged with oily resin. It is of a yellowish colour, often 
* Sim, T. E., The Forests and Forest Flora of Cape Colony, p. lf5S, 
t Sim, T. E., op. cit., p. 1G7. 
