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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



of rough treatment. It may be used like the Aspidistra in places where 

 most plants would soon die. — G. B. 



Poisoning- of Plants by Ammonia. By P. Sorauer (Intemat. 

 phytopath. Dienst. vol. i. No. 2, 1908, p. 61). — Records a case where Azaleas 

 after travelling by train showed signs in the leaves of poisoning by ammonia 

 gas. Since the truck contained no goods except the Azaleas it was 

 surmised that the ammonia must have emanated from its bottom or sides. 

 Inquiries showed that the same truck had just previously carried bags of 

 sulphate of ammonia, and immediately before that cement. The free 

 lime of the cement had presumably disengaged ammonia gas from the 

 ammonium sulphate. The railway authorities being convinced of the 

 reasonableness of this explanation paid compensation to the owner of the 

 Azaleas ! — G. H. P. 



Poisonous effect of Carbon-monoxide. By K. Sulander (Beih. 

 Bot. Centralbt. vol. xxiv. Abth. Heft. 3, pp. 357-883 ; April 1909). The 

 author finds that even one half per cent. o£ this gas has a distinctly injurious 

 effect upon the growth of seedlings. It is also injurious to various fungi 

 inhibiting the germination of spores, growth of hyphae, &c, but no 

 effect upon respiration could be detected by the author's experiments. 

 He suggests that its action may resemble that of chloroform and ether. 



G. F. S.-E. 



Polyporus. By George F. Atkinson (Bot. Ga.z. vol. xlvi. pp. 321- 

 338; November 1908; 5 figs.). — Describes the peculiar structure of 

 the spores of P. lucidus. There are also notes on host plants, distribu- 

 tion, &c, of this and allied species. A new species is described. 



G F. S.-E. 



Potato, Leaf-Roll Disease Of the. By P. Sorauer (Intemat. Phyto- 

 path. Dienst. vol. i. No. 2, 1908, pp. 33-59). — This article deals with the 

 diseases collectively known under the term Curl (Krcitcselkrankheit). The 

 author critically reviews the different opinions which have been expressed 

 from time to time as to the causes of the various forms of leaf curl, and 

 points out that very diverse explanations have been given of its cause and 

 different parasitic fungi have been made responsible for it. In a great 

 many cases which he had studied, parasitic fungi and bacteria were 

 entirely absent. He comes to the conclusion that where such fungi or 

 bacteria have been found they are not the primary cause of the trouble 

 but only secondary accompanying features. He seeks to show that the 

 fundamental cause of all the forms of curl lies in disturbances in the 

 normal equilibrium of the enzymes in the parent "set" or tuber used 

 for seed. Owing' to the richness in sugar of the tubers predisposed to 

 produce this disease and their excess of certain groups of enzymes they 

 offer an extremely suitable nidus for the development of the various 

 bacteria and fungi which have hitherto been looked upon as the primary 

 causes of the disease. A plate showing the different colour reactions 

 given by the juice of healthy and diseased tubers with four enzyme 

 reagents accompanies the paper. — G. H. P. 



