261 



termination of Stereum purpureum wherever it occurs. This is 

 further advisable since it is known that the saprophytic forms 

 have the same injurious effect when inoculated into living trees as 

 those found parasitically. Preliminary measures of a preventive 

 nature are described. 



False Silver leaf is much less prevalent tlnm True Silver leaf. 

 It is easily distinguished by certain microscopic characters. The 

 leaves show a reduction in chloroplasts, which gives them a silver- 

 lead colour from a distance; there is however, no dissolution of the 

 middle lamella, and no falling apart of the cells. No hyphue 



have been observed in any part of a diseased plant. There are 

 no continuous streaks of discoloration to be observed in the wood, 

 and cut-branches do not discolour the water when placed in it. 

 The former is perhaps the only reliable " field character. 

 False Stiver leaf is occasionally found in apples, " Grenadier/'" 

 " Bramleys Seedling/' Camellia Saxanqua var., Koelreuteria 

 paniculata, and rarely on cultivated varieties of Cherries, 

 Peaches and Plums. Trees and shrubs which have suffered from 

 False Silver leaf for one or two seasons have been noted to 

 resume their normal appearance the following year when im- 

 proved cultural treatment has been applied. 



The microscopic examinations and the primary preparations 

 for the inoculation experiments were carried out under the 

 personal supervision of Prof. V. II. TJlaekman, to whom I am 

 much indebted for assistance and valuable suggestions in many 

 directions. 



Bibliography. 



1. Prillieux, Ed. Le Plomb des arbres fruitiers. Bull. d. 

 seances d.l. Soc. Nat. d'Agric. de France. 1885. 



2. Sorauer, P. Milchglanz. Handbueh der Pfianzenkrank- 

 iieiten. 2. Autiage. Band 1. p. 141. Berlin 1880. 3. Autlage. 

 Band 1. p. 285-286. Berlin 1909. 



3. Aderhold, II. Milchglanz des Steinobstes. Zeitschrift der 

 Pflanzenkrankheiten. Bd. 5 p. 86. 



4. Percival, J. Silver leaf Disease. Journal Linnean 

 Society. Botany. Vol. 35, p. 390 % 



5. Massee, G. Conference on Fruitgrowing. Journal of Roy. 

 Hmt. Soc. Vol. 30, p. 35. " Silver leaf." Diseases of culti- 

 vated plants and trees. London. 1910. 



<; Delacroix, G. Maladies des plantes non-parasitaires. 



Vol. 1, p. 227. 



7. Blackinore, G. C. Annual Eeport for New Zealand, Depart, 

 of Agriculture. 1909. p. 53. 



8. Pickering-, S. XT. 6th Eeport TToburn Experimental Fruit 



1906. 12th Heport W 



1910. 



9. Brooks. F. T. Silver leaf disease. Journal of Agricultural 



Science. Vol. IV., p. 13:3. Journal of Agricultural Science. 

 Vol. 5, p. 288. 



