246 EXPERIMENT STATION RECORD. 



The black poplar (Populus nigra), N. Skalosubow (Trudui Byuro Prlkl. Bot., 

 3 {1910), No. 2, pp. JfS, 4.'/ ) .— xU'cordiug to this note the bark of the black 

 poplar is extensively used in Russia in making floats for fish nets. 



The landolphias and the rubber yielding- mascarenhasias, H. Jumelle 

 and H. Perkier {Lcs Laiidolphia ct Ics Mnficarcnhashi a Caoiitrhoiir du nard de 

 UAnaJalava. Paris, 1910, pp. 46, map 1). — A descriptive account is given of 

 the forest regions in northwest Madagascar with special reference to the rubber 

 yielding landolphia vines and mascarenhasia trees. 



Bisks, mistakes and improvements in the rubber production of Asia, 

 D. Sandmann {Tropcnpflanzcr, IJf {1910), Nos. 3, pp. lll-l'tO; ',, pp. 180-206, 

 figs. 17). — The author reviews the beginnings and improvements in the planta- 

 tion rubber industry of tropical Asia, consideration being given to the various 

 species, cultural details, harvesting, and coagulating the latex. 



Analytical investigation of the conception of wood hardness, N. von 

 LoRENZ (Analytisc/ic TJntersucliung dcs Bcgriffcs dcr HrAzhurtc. Vienna, 1909, 

 pp. III). — A theoretical study in which the author endeavors to work out a 

 system of formulas and equations for measuring form pressure and hardness 

 pressure in conducting hardness tests of woods. The application of the various 

 formulas is discussed in connection with a number of hardness pressure tests 

 conducted by G. Janka at the Mariabrunn Forestry Station (E. S. R., 18, p. 

 341), in which prism, wedge, cone and bullet shaped pressure bodies were used. 

 The author endeavors to show to what extent theory has conformed with 

 actual exi)erience as well as the possibility of completing the theory of form 

 pressure and resistance by means of pressure experiments. 



DISEASES OF PLANTS. 



Report of the mycologist, 1907-1909, E. .T. Butler and W. McRae {Rpt. 

 Agr. Research lust, and Col. Pusa [India]. 1907-1909. pp. 6J-68).— Following a 

 description of the institution, its laboratories, and organization, brief accounts 

 are given of the research work that has been begun. This includes studies of 

 disease of sugar cane, coconut palms, citrus fruits, various wilt diseases, and 

 a mulberi-y disease. 



The authors state that the sugar cane disease most prevalent is the red rot, 

 and progress is being made in working out the life history and methods of infec- 

 tion of this disease. In addition the life histories of two other sugar cane 

 parasites are being investigated. 



Successful inoculations with the parasite causing one of the most destructive 

 palm diseases have been secured. The disease of citrus fruits which is occupy- 

 ing most attention is that called white rust, which has proved quite destructive 

 to valuable orange orchards in a number of localities. The disease is said to 

 be Identical with that which has recently appeared in southern Europe, and 

 apparently can be avoided by the choice of stock in grafting citrus plants. 



In a study of wilt diseases the authors' attention has been called to wilt 

 of cotton, indigo, pigeon peas, and chick peas. In all of these the fungus to 

 which the cotton wilt of the United States is attributed was present, but the 

 experimental work has thrown doubt on the parasitism of this species. An 

 entirely distinct organism was isolated from the pigeon i)ea and infection experi- 

 ments have shown it to be the cause of the disease in this crop. This organism 

 has been described as Fusarium udum. A detailed account of the investigations 

 Is to be published later. The experiments indicate the possibility of obtaining 

 a resistant strain of pigeon pea. The cause of the wilt disease of the chick pea 

 has been definitely determined. 



