1919] DISEASES OF PLANTS. 453 



bark in such a way that the wounds will unite by continued inrolling above 

 and below the graft union, and bridging the pinched region with a live layer 

 of bark and cambium, thus eliminating the pinched belt which previously 

 blocked the path of the elaborated sap. 



On a tree of iEsculus pavia killed by Botrytis cinerea, W. B. Beierley 

 {Roy. Bot. Gard. Kew, Bui. Misc. Inform., No. 9-10 (1911), pp. 315-331, pi. 1, 

 figs. 2). — An account is given, with discussion, of the killing of a specimen of 

 ^. pavia supposedly within 15 days after invasion by a fungus, apparently 

 B. cinerea. The tree was killed above the belt of attack, apparently by check- 

 ing very quickly the upward flow of water in the trunk. The tissues below 

 the limit of fungal extension remained alive, exuberantly healthy, while those 

 above soon became dry and shriveled. To determine the nature of the hypo- 

 thetical occlusion of the water-conducting tissues, a thorough comparative 

 examination of tlie diseased tissues was carried out, revealing the presence 

 of approximately ten times as many tyloses in the diseased area as in the 

 corresponding area of healthy wood and suggesting that the stoppage of the 

 upward flow may have been due to their sudden accumulation. 



Discussion is given also of the formation of conidiophorous stromata and 

 of true sclerotia and of the constant relation of these to the lenticels. 



It is stated that features presented by the morphology of the fungus in the 

 tissues are to be described in a later publication. 



Walnut blight [in South. Africa], E. M. Doidge (So. African Fruit Grower, 

 5 (1918), No. 4, PP- 68, 69, figs. 2). — Walnut blight appearing recently in por- 

 tions of South Africa is said to have been shown by investigations to be due to 

 Bacterium juglandis, which is identical with the organism causing a similar 

 disease in America and New Zealand. The blight appears to have been intro- 

 duced with nursery stock, and to be greatly favored by the prevalence of rain 

 and mist in spring and early summer during the growth of the nuts, many or 

 most of which may drop at an early stage of development. The disease is 

 carried over in leaves and in the lesions on the twigs. 



Note on Polysaccum crassipes: A common fungus in eucalyptus planta- 

 tions around Pretoria, P. A. van der Bi.tl {Trans. Roy. Soc. So. Africa, 6 (1917), 

 pt. 3, pp. 209-213, pis. 6). — The author gives a brief note on P. crassipes, which 

 is a very common fungus in eucalyptus plantations around Pretoria. It is 

 suggested that the relation between fungus and host is that of symbiosis, as 

 the tissues of the plant do not appear to suffer from the presence of the fungus. 

 Reference is made to the earlier and more general works on symbiosis. 



Heart rot of Ptaeroxylon utile caused by Pomes rimosus, P. A. van deb 

 BijL (Trans. Roy. Soc. So. Africa, 6 (1911), pt. 3, pp. 215-225, pis. 6).— The 

 author gives an account of heart-rot disease in P. utile, ascribed to F. rimosus, 

 as regards distribution of the fungus and its effect on the wood. This fungus 

 is stated to have been reported in the Union of South Africa on 11 genera 

 belonging to 8 different natural orders. 



Decayed wood and the fungi therein as seen with the microscope, H. N. Lee 

 (Trans. Nat. Assoc. Cotton Manfrs., No. 102 (1917), pp. 220-226, figs. 6),— This 

 is a preliminary description of the effect of important wood destroying fungi 

 on structural timbers taken from cotton mills and of the appearance of the 

 fungi in the wood, with an outline of projected study to identify the fungi in 

 the absence of fruiting bodies. 



The decay of timbers in buildings, R. J. Blair (Trans. Nat. Assoc. Cotton 

 Manfrs., No. 102 (1917), pp. 2^2-250, figs. (?).— The question of decaying wood 

 being considered as mainly, if not purely, a matter of moisture (relative 

 humidity), an account is given illustrating the operation of this factor; also of 



