218 Transactions of the Royal Society of South Africa. 



The Sneezewood trees are particularly favourable to this method of infec- 

 tion ; the branches are brittle and easily broken off, and the tree is slow- 

 growing and relatively poor in sapwood, conditions favourable to the entrance 

 of the fungus. 



Mr. J. D. Keet, District Forest Officer, who has had this fubgus under 

 observation for some time, in reply to a question re the distribution of this 

 fungus, states : " It is worse in forests more heavily stocked with Sneeze- 

 wood and such forests — in the Eastern Conservancy — belong entirely to the 

 ' Low Type Forests.' In the ' High Forests,' Sneezewood occurs mostly 

 on the stony, drier ridges, but while the individual trees are much bigger 

 they are few and far between. In such forests Sneezewood is very seldom 

 attacked by Fomes rimosus, although, strange to say, Black Ironwood (Olea 

 laurifolia) may here be attacked." I have examined the fungus from Black 

 Ironwood and verified Mr. Keet's statement that it is Fomes rimosus. 



The elevation of the Grxulu forest where this fungus is particularly abun- 

 danton Sneezewood variesfrom3300-3600ft. Thefungus,as mentioned above> 

 causes the heartwood of the tree to rot, and as a result the tree, though it 

 remains standing and growing, is hollowed in the centre. This hollowing is 

 easily evident by tapping the tree. The rotten wood usually crumbles into 

 a dark brown powder, and natives make holes in diseased trees to get at 

 this mixture of rotten wood and fungus, which they use for tinder and know 

 as " viti." The fruiting bodies or sporophores of the fungus are often found 

 high up on the branches, and as noted always in association with a wound 

 or scars of former branches. The natives know the sporophores under the 

 name " Sbeni " (liver). The sporophores are hoof -shaped, with a black 

 cracked surface (hence the second name of the fungus). 



A transverse cut (Fig. 3) through a diseased trunk in its earlier stages 

 shows a number of yellowish-brown poclfets usually surrounded by a Vandyke 

 brown margin. These pockets are arranged more or less concentrically and 

 extend outwards in radial lines. 



In a tangential section these pockets stand out as lens-shaped masses. 

 The yellowish-brown mass, which represents nothing less than a felt-like 

 mass of fungus threads, can be readily lifted out of the pocket. Fig. 4 

 shows some empty pockets from which the fungus has dropped. 



By the spread of the fungus, both longitudinally through the wood 

 elements and transversely through the medullary rays and pits, the rotten 

 wood is gradually added to until ultimately only the sapwood and the bast 

 exterior to it remain. It is seldom that the fungus attacks the sapwood, and 

 if it does the death of the tree is certain. 



Not always is the stem merely hollowed out as above described, but the 

 fungus also forms masses of felted tissue in the decayed area. Fig. 5 

 represents a mass of felt-like fungous threads matted together and taken 

 from a hollow Sneezewood tree. This particular mass was almost white. 



