FOMES APPLAN ATI'S ( I'KKS. ) VVALLR. IN SOUTH AFRICA. 487 



trees of Olca laiirifolla (black ironwood) ; on stumps of Acacia 

 molissima (cultivated wattle); Melia Azcdaracl\ (Syringa); on 

 dead and also on live Rhus hcvujata (red currant) ; Cnrtisia 

 fagiuca (asseg^ai wood) ; (^n dead and also in wounds of Triclio- 

 cladits sp. (tuiderbush) ; bole of dead but standing Podocarpus 

 sp. (yellow wood) ; in wound of live P\nis cojiiiiiitiiis (culti- 

 vated pear); Ccltis Kraiissiana ( Canideboo stinkwood); dead 

 log of Scolopia Miindii (red pear). Many sjiecimens have been 

 entered up as growing on dead logs, which were not possible to 

 name, and the above list will later jirobably have to be con- 

 siderably enlarged. 



The Funcus on Black Ikoxwood {Olca Jaiirifolia). 



Sim,* treating of Olca laitrifolia, writes: 



Trees which appear quite sound f)ut\varclly are often found to be 

 more or less decayed inside, even without showing much evidence of that 

 in the cross-cut. hut the sound parts of such a tree are not rendered untit 

 thereby. 



The above is the only reference to a decay Oif black iron- 

 wood trees in South Africa, and whether Sim had this fungus 

 or Pomes rimosus, which less freciuently may occur on the same 

 host, in view, I do not know. 



The loss of black ironwood trees owing to attack h\ this 

 fungus must be considerable, as I had an opportunity of seeing 

 for myself when, in 191 5, in company with Mr. J. D. Keet, of 

 the Forestry Department. I visited several of the forests of 

 the Eastern Conservancy. 



As a result of the decay induced by this fimgus the trees 

 are weakened, and are easily blown over by the wind. Fre- 

 quently the sporophores of the fungus develop only after the 

 tree has been blown over, but they have also been observed at 

 the base of li\e black ironwood trees, and there can be on doul)t 

 about this fungus being directly responsible for the decav and 

 ultimate blowing oxer and death of these trees. 



The fungus in most cases probably gains entrance through 

 small wounds or abrasions near the soil level, a i)lace which, 

 since it is usually somewhat moist, would favour the develop- 

 ment and growth of external mycelia of the fungus. The trees 

 affected are invariably full-grown, though it can hardlv be held 

 that their vitality had become impaired ])rior to infection by the 

 fungus. Furthermore, in no case obser\ed in black ironwood 

 was there any large wound, such as \on Schrenk and Sjjaulding 

 would appear invariably to associate with the cotton-wood 

 disease. The attacked ])art is soft and ])unky, and the 

 decayed wood in the dry condition is readily crtmibled 

 between the lingers. We come next to consider the 

 action of the fungus on the wood. Figure i illustrates a tran.s- 

 verse section, which had been treated with chlorozinc iodide. 

 The lamelUe bordering the lumina readily lake the cellulose 



* Sim. T. f^.. '■ The Forests and Forest Flora of Cape Colony." p. 265. 



