DISEASES OF PLANTS. 543 



penetrate into tlie tissues of the host. He, therefore, coucliules that the origuiai 

 entrance of germ tulies into the host is due to cheuiotropic influences. 



The dissemination of disease by means of the seed of the host plant, 

 M. F. Barkus (Pioc. Inil. Acad. ticL, 1908, pp. llS-122, pi a: 3). — This is an ab- 

 stract of a thesis in which the author gives data regarding a number of dis- 

 eases which are transmitted from crop to crop through the seed. These dis- 

 eases are divided into two classes, (1) those in which the organism enters the 

 maturing seed and exists within in a dormant condition until the germination 

 of the seed, and (2) those whicli adhere to the surface of the see<l, entering the 

 host plant at the time it germinates. 



The diseases described are bean anthracnose (Collctotrichum lindemntlii- 

 anuin), sunscald of pea {Ascochyta pisi), loose smut of wheat (Ustilago tritici), 

 naked smut of barley {U. nuda), stinking smut of wheat {TiUetia foetens and 

 T. tritici), loose smut of oats (U. avence), hidden smut of oats {TJ. Icevis), 

 covered smut of barley (17. hordei), the smuts of a number of other plants, flax 

 wilt (Fusariuin lini), bacterial blight of beans, black rot of cabbage, and 

 Stewart's bacterial disease of corn. In addition it is suggested that some spe- 

 cies of rusts may be carried over in a similar manner. 



Some Fusarium diseases of plants, K. voN Tubeuf (Mitt. K. Bayr. Moor- 

 kiiJturanst., 1008, Xo. 2, pp. 38-62, pi. 1, figs. 4)- — A summary is given of investi- 

 gations on the diseases of plants due to various species of Fusarium, after 

 which the species attacking grasses and common cereals are described at some 

 length. Among the species occurring on these hosts are F. heterosporum, F. 

 tritici, F. culmonun, F. hordei, F. lolii, etc. 



The perithecial stages of Fusariums are discussed at some length and notes 

 are given on the color changes observed in different species. 



The heteroecious plant rusts of Indiana, A. G. Johnson (Proc. Ind. Acad. 

 Sci., 1908, pp. 87-9 Ji). — The author briefly shows the results of investigations in 

 connecting various forms of rusts with their different host plants, and gives 

 the life histories of 34 species of rusts represented in Indiana. The aecidial 

 stages of a number of others are not yet known and the teleutospore stages of 

 a considerable number of species^ are not yet recognized. 



International statistics of the grain rusts, P. Sorauer (Zt.schr. Pflanzen- 

 krank., 1!) (1909), Xo. -'i-5, pp. 193-286). — This is a comprehensive investigation 

 and compilation of data on the grain rusts of the world. 



The material is arranged in the following manner: (1) Events which illus- 

 trate the severity of the rust at certain seasons or periods. This includes in- 

 stances of severe rusting in which the entire crop of grain was practically 

 destroyed, and those in which the plants were badly rusted but a fair crop was 

 harvested in spite of the rust. (2) Theories as to the means of infection and 

 propagation of the rust that have been advanced by various writers. Eriksson's 

 experiments on which he based his mycoplasm theory as to primary infection 

 are given, and results obtained by various workers from inoculations of jecidio, 

 uredo, and teleutospores on different host plants are noted. (3) The influence 

 of the weather on the origin and distribution of the rusts. The effects of rain- 

 fall, sudden changes of weather, and the weakened condition of the grain plants 

 due to hail, drought, humidity, insect injuries, frost, or other debilitating 

 agencies, are each given due attention. (4) The location and nature of the 

 soil in reference to the appearance of the rusts. Here are set forth the data as 

 to the different kinds of soils (clay, sand, loam, etc.), subsoils, and location as 

 to drainage and their probable bearing, if any, on the rusting of cereals grown 

 on them. (5) The influence of cultural methods on the severity of rust attacks. 

 The subdivisions under this heading are good seed, thickness of stand, seed 



