DISEASES OF PLANTS. 451 



through proper managemeut. It is estimated that there is an unutilized area 

 of 80,000,0(10 acres within our present producing forest, in addition to 135,- 

 000,000 acres of unproductive forest land within our virgin or mature forests, 

 and 90,000,000 acres of waste lands which can be made productive by planting 

 or fire protection. 



Increment studies in a spruce stand, A. Schiffel (ZuiDaclisstudien in einem 

 Fichtcnbesfandc. ^'ienna, 1909, pp. 25; abst. in Centbl. Gesam. Forstiv., 35 

 (1909), No. 12, pp. 505-527). — A detailed account with tabular data is given of 

 a large number of increment measurements made in an SO-year old spruce 

 stand which was thinned out at 4 different periods between 1903 and 190S. 



Selection of seeds in forestry, P. Guinieb (Ann. Sci. Agron., 3. set:, 4 (1909), 

 II, JVo. 6, pp. JfJf4-JtG9). — The author discusses the importance of selection as a 

 means for improving timber species and reviews the literature on the subject 

 of variation among forest species. 



Trees of California, W. L. Jepson (San Francisco, 1909, pp. 228, pis. 33, figs. 

 83). — This is intended as a popular working manual of the native trees of 

 California. It contains botanical descriptions of trees arranged according to 

 families, together with information relative to their geographic distribution 

 and economic value. 



Illustrations of conifers, H. Clinton-Baker (Hertford, 1909, vol. 2, pp. 79, 

 pis. 91). — A continuation of the series of life-size illustrations of the cones and 

 foliage of conifers growing in the British Isles, supplemented by analytical keys 

 to species and short concise descriptions, previously noted (E. S. R., 22, p. 145). 



Eucalyptus culture, E. Navarro de Andrade (A Cultara do Eucalyptus. Sao 

 >^aulo, 1909, pp. VIII +156, pis. 15). — Part 1 of this work treats of the general 

 characters and descriptive botany of the eucalypts and part 2 discusses the 

 details of eucalyptus culture, including climatic and soil conditions, trans- 

 planting and planting operations, subsequent culture, exploitation, destructive 

 insects, cost of planting operations, yields, and returns in major and minor 

 forest products. The subject-matter is based upon the available literature of 

 the eucalypts, together with planting trials conducted during the past 5 years 

 at the Jundiahy arboretum, near Sao Paulo, Brazil. A descriptive account of 

 this arboretum is appended. 



A study of rubber-yielding' latexes and the methods of making' rubber, 

 C. E. DE Mello Geraldes (Estac. Agr. Cent. [Mexico] Bol. 6, pp. 129). — This is 

 a Spanish translation made by G. Gomez of the author's review of our present 

 knowledge of caoutchouc-bearing latexes and of methods of preparing rubber 

 from latexes. 



[An expedition in search, of rubber yielding- plants], A. Opazo and C. 

 Reiche (An Agron. [Santiago de Ghili], .'/ (1909), Ao. 3-//, pp. 189-237, figs. 16, 

 dgm. 1). — The report of a search conducted in the Province of Atacama, Chili, 

 for rubber yielding species, together with an account of the botanical char- 

 acters, occurrence and tests of a latex -yielding euphorbia (Euphorbia lactiflua). 

 Analyses of this latex made at the Agronomic Station, Santiago, Chili, show 

 it to have a resin content of about 28 per cent and with only about 4.1 per cent 

 of insoluble gum. The plant is not considered worth exploiting commercially. 



DISEASES OF PLANTS. 



Cultures of Uredinese in 1908, J. C. Arthur (Mycologia, 1 (1909), No. 6, pp. 

 225-256). — In continuation of investigations on heteroecious fungi (E. S. R., 

 20, p. 52) the author gives a detailed report on studies on the grass and cedar 

 rusts and also on the advance made in segregating the subepidermal rusts 

 which have generally passed under the name of Puccinia rubigo-vera. 



