48 EXPERIMENT STATION RECORD. [VoL 88 



groups, the first consisting of P. grwminis tritici, P. gramimAs tritici compacti, 

 and P. graminis secalis; the second of P. graminis aven<e, P. gramims phlei- 

 pratensis, and P. graminis agrostis. For group 1, wheat, club wheat, rye, and 

 Agropyron repens are said to be differ^itial hosts; while for group 2, oats, 

 Phleum pratcnse, and Agrostis spp. serve a similar purpose. Barley, rye, and 

 Bromus tectorum have been found infected by all six biologic forms, and 

 oats is reported as being infected by all but P. graminis tritici compacti. The 

 biologic forms are said to be distinguished from each other morphologically 

 as well as parasitically. 



Some notes are given on observations on the overwintering of the uredinial 

 stage on grass hosts, but definite conclusions have not been reached, except 

 for P. graminis phleipratensis, which survived the severe winter of 1916-17 

 at St. Paul, Minn. 



Some diseases of wheat crops and their treatments, W. J. Spajffobd {Jour. 

 Dept. Agr. So. Aust., 20 (1917), No. 7, pp. 5S1-548).— It is stated that of the 

 smuts in South Australia, TiUetia tHtici is by far the worst, loose smut 

 (VstUago tritici) is fairly common (doing but little damage), and flag smut 

 (Urocystis tritici) somewhat reduces the wheat crop. Of other diseases, take- 

 all (Ophiobolus graminis) is becoming increasingly troublesome in many dis- 

 tricts, and red rust [Puccinia graminis) does not use the barberry as alter- 

 nate host in Australia, being carried over the winter supposedly on some native 

 grasses. Mildew (Erys^iphe grwminis) is becoming more or less common In 

 wheat fields, where it is thou^t it may develop into a serious pest under the 

 conditions prevalent in this region. 



Some important diseases of truck crops in Florida, C. D. Sheebakoff 

 (PloHda Sta. Bui. 1S9 (1911), pp. 191-277, figs. 58).— The author gives descrip- 

 tions of the more important diseases affecting different truck crops in Morida 

 and offers suggestions for their control. 



Common diseases of beans and peas, M. T. Cook (New Jersey Stas. C-irc 84 

 (1917), pp. 2-8, figs. 4). — This is in part a revision of Circular 50, previously 

 noted (E. S. R., 35, p. 245). 



Toxic chlorosis of maize, P. Maz6 (Compt. Rend. Soc. Biol. [Peris], 75 

 (1916), No. 19, pp. 1059-1066). — In the course of a study of chlorosis of maize, 

 as previously noted (B. S. R., 33, p. 522), the author has found that a form of 

 chlorosis different from that caused by a lack of sulphur and of iron can be 

 produced experimentally, being due to a sort of intoxication of the plant. On 

 the other hand, cell sap from the normal leaves, when deposited on the 

 etiolated leaves, causes a return of the normal green color in the cells. This 

 curative property of normal juices may disappear for a time iinder the influence 

 of certain atmospheric conditions. This restorative substance is thought to be 

 elaborated by protoplasmic activity which may produce an internal secretion, 

 the function of which is to guard the plant against accidental intoxications 

 and parasitic diseases. 



It was found that the addition of lead or of methyl alcohol to a nutritive 

 solution which is described, or the removal of zinc therefrom, would cause a 

 toxic chlorosis of maize which was relieved by applying to the etiolated ceUs 

 an exudate of normal leaves or an extract of the crushed leaves. The pa- 

 renchymal cells of normal leaves of maize are thought to secrete a substance 

 which may prevent the intoxication due to any of several causes, and which 

 may prevent also attack by parasitic insects. 



Studies in the mosaic diseases of plants, G. W. Freibekq (Ann. Missouri 

 Bot. Gard., 4 (1917), No. 2, pp. 175-232, pis. 4).— Summarizing the evidence 

 presented in this paper and by other workers on mosaic diseases, the author 

 states that these are not caused by unbalanced inorganic nutrition, inorganic 



