136 Pflanzenkrankheiten. 



mixture before the bursting of the buds. The ingredients of the 

 Burgundy mixture were mixed when quite cold, and in some ot the 

 experiments milk was added, with good results. 



E. M. Wakefield (Kew). 



Long, W. H., A preliminary note on Polyporus dryadeus as 

 a root parasite on the oak. (Phytopathology. III. p, 285—287. 

 1913.) 



The writer found Polyporus dryadeus attacking the roots of 

 Quercus texana, Q. nigra^ Q. alba, Q. velutina, Q. minor, Q. rubra and 

 Q. prinus. No rhizomorphs af any kind were found associated with 

 this rot, either beneath the bark, or on the surface of the diseased 

 roots, or ramifying in the adjacent soil. Authentic specimens of P. 

 dryadeus from America, England, France, Germany and 

 Aus tri a were examined by the writer and a careful comparison 

 with the material used as the basis of this article showed that the 

 American fungus under discussion is undoubtedly identical with the 

 European plant known as P. dryadeus. 



Polyporus dryadeus is therefore a root parasite on the oak pro- 

 ducing a white sap and heart-rot in the roots. In the majority of 

 cases only old trees or trees much suppressed and growing under 

 unfavorable conditions were found attacked by this fungus. The 

 disease does not seem to spread readily to adjacent trees. 



M. J. Sirks (Haarlem). 



Lutman, B. F., The pathological anatomy of potato scab. 

 (Phytopathology. III. p. 255—264. 1913.) 



The writer summarizes his paper as follows: 



1. The scabs ma}^ originate at any place on the potato, but 

 frequently occur at lenticels. 



2. The scab is due to the hypertrophy of the cells of the cork 

 cambium. This condition is always accompanied in deep scabs by 

 a hyperplasie of that layer, due to its continued regeneration from 

 the outer cells of the starch parenchyma. The walls of the hyper- 

 trophied cells are much thickened, due to their suberisation. 



3. In surface view of brown spots on the skin of scabby potatoes 

 and in very young scabs, there can be seen in glycerine mounts, 

 the threadlike filaments of the fungus which apparentl}^ produces 

 the disease. 



4. There accur in the cork cambium and in the outer layers of 

 the starch parenchyma, instead of starch grains, great numbers of 

 fat globules of varying size. These bodies are one of the results of 

 the disease. The carbohydrate material is stored in the tissues 

 affected by it in this form. M. J. Sirks (Haarlem). 



Orton, W. A., International , phytopathology and qua- 

 rantine legislation. (Phytopathology. III. p. 143 — 151. 1913.) 



The paper gives a brief discussion of the problems of internatio- 

 nal phytopatholog}'' with especial reference to the needs developed 

 in applying legislative means for the control of plant diseases and 

 an outline of the Federal Plant Quarantine Act of August 20, 1912. 



The essential features of this law are pointed out; the quaran- 

 tine notices no. 1 (Sept. 16, 1912) — no. 7 (May 21, 1913) are discussed. 



Emphasis has been placed on the research phases rather than 



