1919] DISI \SE8 OF PLANTS. 253 



Experimental investigations on the genus Razoumofskya, J. R. WEB (Bot. 

 Goaf., 66 (1918), No. 1, pp. 1-3 1. figs. t9).—In this article, the first of a proposed 

 series, it is claimed that B. campylopoda and /.'. oryptopoda are not identical, 

 each form exhibiting considerable variation with host and with geographic 

 locution, a*, oatnpylopoda can infect pinus resinosa, and its Invasion of eastern 

 United States is feared. It can also infect /'. sylvestria and P. montana, and 

 may be a source of danger to interests in Europe. Apparently It. occidentalis 

 a hi, tin a la a biological form of R. campylopoda. 



R. lands will infect Larlx europea, L. leptolepis, Abies grandia, P. ponderosa, 

 and /'. oontorta, all except the last named being new hosts for this species. 

 Apparently this parasite infects Japanese and European larch. It is, so far 

 as known at present, of economic importance only on L. occidentalis. 



R. douglasii abiitina is identical with R. douglasii, which is of importance 

 only in connection with Pseudotsuga taxfolia. R. anierieana can infect both 

 hard and soft pines, being of importance on Pinus oontorta and P. banksiana. 

 B. tsugensis can infect A. lasiocarpa and Tsuga canadensis. 



Many characters of false mistletoes vary with change of host, geographic 

 location, and various environmental factors, this circumstance suggesting that 

 only the broader and more plainly evident lines should be observed in classifica- 

 tion. 



Injury to evergreens, G. V. Nash (Jour. N. Y. Bot. Gard., 19 (1918), Nos. 

 219. pp. J f S-50; 223, pp. 159-16J f ).— The author shows that after withstanding 

 from February 5 to 15, 1918. temperatures ranging between — 6 and + 54° F. 

 with somewhat sudden changes, the soil remaining frozen during the whole 

 period, severe injury was inflicted on evergreens in the New York Botanical 

 Garden on February 15, when the temperature rose to 5G°. Wind is con- 

 sidered as a most important factor. Reference is made to the degree of injury 

 noted in March to certain evergreens which were affected during this period. 



In the second note, written late in June, an account is given of developments 

 subsequent to the time reported upon previously. A list is given of evergreens 

 which proved unsatisfactory under the severe conditions of the 1918 winter. 



Resistance of oaks to Oidium, L. Montemartini (Riv. Patol. Yeg., 9 (1918), 

 No. 5-6, pp. 77-79). — The author has given to American oaks a study along the 

 lines followed by Pantanelli (E. S. R.. 34, p. 650) on European species. He 

 announces as a result of analytical determinations that in American oaks the 

 conditions of receptivity are stability and coincidentally a ratio of more than 

 1:2 between soluble and insoluble nitrogen, the latter form greatly predominat- 

 ing in the American oaks examined. 



[Diseases affecting rubber production], T. Wubth (Meded. Proefstat. Ma- 

 lang, No. 22 (1918), pp. 7-15). — This report deals in a somewhat general way 

 with injury to rubber interests through such agencies as canker, scab, leaf dis- 

 eases, sheet mold, mistiness, and greasy and other abnormal appearances of 

 sheet rubber, with a discussion of some preventive or remedial measures. 



A method for determining the fungicidal coefficient of lime-sulphur and 

 other common fungicides, H. C. Young and E2. II. Cooper (Arm. Bpt. Mich. 

 Acad. Sri., 19 (1917). pp. 221-236) .—The authors have devised a method for the 

 laboratory determination of the copper sulphate coefficient of fungicides, de- 

 pending upon comparison with a phenol solution of standard strength. Several 

 commercial preparations of lime sulphur, ammoniacal copper carbonate, and 

 neutral copper acetate have been tested, the organisms employed for this pur- 

 pose being Olomerella rufomaculana and Endothia parasitica. 



109G42 — 19 5 



