ABSTRACTS. 



1183 



and quite conspicuous. Many of them adhere very firmly. The hyphae 

 spread through the soil in various directions ; hence a single diseased 

 Potato may be the means of infecting an area of considerable size. 



Plants which are attacked when young, if not killed outright, are often 

 dwarfed, and frequently die long before the close of the season. The 

 parts below ground are thoroughly infected with the Rhizoctonia. In 

 some cases the disease attacks the plant just below the surface of the 

 ground, and under favourable conditions a stem rot called "Collar Rot ,r 

 or "Black Ring " is produced. When the attacks on the stem are not so 

 oevere as to cause death the injuries may prevent the assimilated food 

 from being stored in the subterranean portion of the plant, large tops- 

 are produced, and green tubers often form in the axils of the leaves. 



It is unnecessary to refer here to the inoculation experiments, except 

 to state that they confirm the above conclusions. 



It is confessed to be difficult to treat this disease, as there is no 

 practical method of checking its spread after it is once introduced into 

 the soil. The only way of dealing with it is by preventive means. A 

 heavy poorly drained soil seems to favour the disease. It is recommended 

 to treat seed Potatos with a corrosive sublimate solution a week before 

 planting, spreading them on the floor or ground in the sunlight there- 

 after, 



Treatment with formalin, of which eight ounces to fifteen gallons of 

 water should be used, is recommended, and the seed Potatos soaked 

 therein for two hours. 



Seed Potatos should be carefully sorted, disinfected, and planted on 

 land that is well under-drained. Then, by practising a long and systematic 

 rotation of crops, the soil may be prevented from becoming badly infected 

 with the disease. — M. C. C. 



Potato Scab. By H. Garman (U.S.A. Exp. Stn. Kentucky, Rep. 

 1898, p. 9). — Experiments were carried out to determine to what extent 

 scabbing of Potatos was due to the introduction of a fungus into the soil 

 with seed Potatos, and how far the disease is the work of organisms which 

 live in the soil. Corrosive sublimate (4^ oz. in 30 galls, of water) was 

 found the most effective bath in which to soak the seed Potatos in order 

 to kill the fungus (Oospora scabies). The Potatos should be soaked for 

 one hour. The percentage of scabbed Potatos in the crop was reduced 

 from an average of 93 per cent, to an average of 29*7 per cent, by the use 

 of corrosive sublimate. — F. J. C. 



Potato; Trials with Fertilisers (U.S.A. Exp. Stn. Kentucky, 

 Rep. 1898). — Gives tables showing the results of experiments with a 

 variety of fertilisers. The addition of potash and nitrogen each gave an 

 increased yield, but the best results were obtained by the use of a com- 

 bination of the two. — F. J. C. 



Potentillas. By M. H. (Gard. Mag.Xo. 2537, p. 361 ; 11 6 1902).— 

 The writer of the article on these beautiful and comparatively little- 

 known border flowers evidently knows all about them, as he gives all the 

 information required for their culture and propagation, as well as the 

 places best suited for them in a garden. A list of the finest varieties is 



