1919] DISEASES OF PLANTS. 345 



Hawaiian Islands. These include some species of Acacia and Sophora and 

 single representatives of Mezoneuruni and Erythrina. 



The production of aspen, G. Schotte (Meddel. Stat. SliOffsforsoksanst., No. 

 13-lIf {1916-11), pt. 2, pp. 1205-1219, CXLVII-CXLVIII, figs. 5; also in Skogs- 

 vdrdsffir. Tidskr., No. 11-12 {1918), pp. 641-655, figs, 5).— A preliminary study 

 of production in several experimental stands of aspen leads the author to con- 

 clude that the aspen when grown on good soils in Sweden is a valuahle tree 

 that merits being well cared for. The aspen is used primarily in the match 

 industry. 



The larch and its importance in Swedish, forest economy, G. Schotte 

 (Meddel. Stat. Skogsforsoksanst, No. IS-U {1916-17), pt. '2, pp. 529-8^0, LIX- 

 LXXXIV, pis. 10, figs. 107). — ^An account of the results thus far attained in the 

 cultivation of different kinds of larches in Sweden, as studied in some 66 experi- 

 mental plats, in mixed or pure larch stands, belonging to the Swedish State 

 Institute of Experimental Forestry. Swedish literature dealing with the forest 

 (lualities of the larch is perused and cited almost in its entirety, and the foreign 

 literature, especially German and English works, is also reviewed. 



The cultivation of osiers and willows, W. P. Ellmore, edited by T. Okey 

 {London and Toronto: J. M. Dent & Sons, Ltd., 1919, pp. X+96, pis. 9). — A prac- 

 tical treatise on willow cultivation and the preparation of osiers for market, 

 based upon articles originally published by the author and editor in the Journal 

 of the Board of Agrieulture. The subject matter is discussed under the general 

 headings of the cultivation of basket willows, expenses and returns, varieties 

 of willows, preparation and marketing, insect pests of basket willows, and tree 

 willows. 



Rubber plants, II. ISI. Hall and F. Long {Carnegie Inst. Washington Year 

 Book, 17 {1918), p. 297). — An extensive survey of the Great Basin region for 

 nil)ber-produciug plants, begun in 1917 as a war emergency project, has broad- 

 ened out during 1918 into a comprehensive search throughout the West. It 

 is proposed to continue this work. Rubber has been found in 2.5 of the species 

 examined, the percentage being sufficiently high in 11 species to justify further 

 investigation, and sufficiently high in 4 to warrant the hope that these species 

 may serve as a basis for rubber production on a commercial scale. 



A further note on thitsi (MelanorrhcBa usitata), with special reference to 

 the oleo-resin obtained from it in the Lawksawk and Myelat States, South- 

 ern Shan States Forest Division, F. A. Wright {Indian Forest Rec, 7 {1919), 

 No. 2, pp. IJ), pi. 1). — The present paper is supplementary to one previously 

 issued on the same subject by Benskin and Rodger (E. S. R., 38, p. 247), and 

 contains mucli information on the subject of tapping this species for oleo-resin. 



DISEASES OF PLANTS. 



Plant disease inquiries, .1. J. Thornber {Arizona 8ta. Rpt. 1917, pp. 431, 

 Jf.32). — The author reports the occuri-ence of a root rot of white sweet clover 

 due to Ozonium omnit^erum, early potato blight, sore shin and angular leaf 

 spot diseases of cotton, tomato wilt, a dry-rot disease of the potato caused by 

 si>ecies of Fusarium, and a serious disease of date fruits. The last disease 

 affects both green and ripe fruit at the Yuma date orchard, at least 90 per 

 cent of the crop of the year being damaged. The fruits become mummified 

 and acquire a bitter taste, thus being rendered unfit for use. Three species 

 of fungi have been found associated with this disease, which is in process of 

 further investigation. 



