DISEASES OF PLANTS. 953 



preservative materials in prolonging the life of limbers. A discussion is pre- 

 sented of wood preservatiou, the nature of decay, and the methods of retarding 

 it by seasoning and by chemical Impregnation, with an account of the various 

 preservatives and processes in use in the United States. The economic value 

 of wood preservation and its influence on forestry in the future is also discussed. 

 Notes on rubber cultivation, J. A. Wyllie and O. G. Ferreira (Eladrafi, 

 1907, pp. A'/r+i,i/, /*/,s-. /()■). — These notes deal with the cultiu-e and exploita- 

 tion of the important rubber-producing species in various tropical countries, 

 with special reference to the development of the industry in Portuguese India, 

 and include the botanical description, soil and climatic conditions, habits, 

 methods of reproduction, planting, harvesting, and preparation of the rubber. 

 Numerous estimates are given with regard to returns secured from capital in- 

 vested, and the work concludes with a chapter devoted to a discussion of the 

 lessons to be learned from the Ceylon rubber exhibition of 1906. 



DISEASES OF PLANTS. 



Some diseases of Rocky Mountain plants, I.. II. Pammel (Proc. Iowa Acad. 

 Sci., 13 (tUOU), pp. S'.l-ll'i. pis. 6). — The author describes the geographical dis- 

 tribution and host plants, general and microscopical characters, and economic 

 aspects of a number of fungus and other parasites observed on some Rocky 

 Mountain plants. Among the fungi noted are Pcridcrmium cerehrum. P. 

 chitinum, P. aMetinum, Exoascus nanus, E. cerasi, Taphrina cwrulescens, 

 Podosphwra oxyacanthw, Phyllactinia suffulta, UncinuJa salicis, Ploiorightia 

 morhosa, etc. The phsenogamic parasites described are ArceuthoMum rohustuni, 

 A. aincricanum, and A. douglasii, which occur on various coniferous trees. 



A northwest tuckahoe, J. Fletcher {Canada Expt. Farms Rpts. 1906, pp. 

 232-23'/, pi. 1). — A description is given of a sclerotium form of some fungus, 

 probably a Polyporus, which is more or less frequently met with in parts of 

 Canada. They are usually found during the process of plowing land and excite 

 considerable interest. Specimens have been found surrounding pieces of wood, 

 and it appears probable that the fungus is at first parasitic on certain species of 

 poplars and perhaps also on willows. 



Investigations on some imperfect fungi and their associated ascomycetous 

 forms, II. Klebahn (Ztschi: Pflaiizcnkrank., 11 {1901), Xo. .',, pp. 223-231, pi. 1, 

 figs. 2). — The ascospoi'e form of Marssonia jiiglaiidis and the various reputedly 

 associated fungi have been subjects of investigation by means of cultures and 

 inoculation experiments. The author is convinced of the relation between 

 M. jiiglandls and Gnomonia Icptosighi, or Glwosporitini juglandis, as it is often 

 referred to. 



The author states that as no perennial mycelium or other special device for 

 wintering the fungus has been found, it must pass the winter in fallen leaves, 

 and for the prevention of the spread of the disease these should be collected 

 and destroyed. 



Fungus diseases and spraying, W. T. Macoun {Canada Expt. Farms Rpts. 

 1906, pp. 121-12'/). — After giving a brief account of the more troublesome dis- 

 eases observed during the season, the author desci-ibes pear blight, the sooty or 

 fly-speck disease of apples, black rot of tomatoes, and onion blight or mildew. 



For pear blight cutting out the infested areas and treating the cut surfaces 

 Avith some antiseptic is recommended. 



The sooty or fly-speck fungus {Leptollii/riiini ponii) is said to have caused 

 more trouble than usual, disfiguring much fruit. The fungus develops in the 

 sunnner, after the time when the trees are ordinarily sprayed, so that an addi- 

 tional spraying is recommended for its i)reventiou. 



