646 EXPERIMENT STATION RECORD. 



cross-fertilization between tbe 2 strains, as is shown by the fact that ascospores 

 in the same perithecinui develop both strains on culturing. 



On some resemblances of crown gall to human cancer, E. F. Smith {Science, 

 n. set:, 35 (UIU), No. 802, irp. 161-172). — This is the address of the retiring 

 president of the Botanical Society of America, delivered December 28, 1911, a 

 preliminary account of the investigations having been given elsewhere (E. S, R., 

 25, p. C)r)0). 



The relation of stem diseases to soils, K. Ewert {Dent. Ohfithau Ztg., 1912, 

 A^o. 2, J}]). 29-Sl, fly. 1). — The author calls attention to the necessity of a closer 

 study of the underground life of plants and of the relations of pomologj' to 

 geology. 



Report of the bacteriologist, W. G. Sackett {Colorado 8ta. Rpt. 1910, pp. 

 91-93). — This contains a summary report of investigations on the bacterial 

 disease of alfalfa (E. S. R., 23, p. 54G), bacteriological studies of alkali soils 

 (E. S. R., 25, p. 815), and studies of the hold-over blight in the pear and 

 apple (E. S. R., 25, p. 848) and of raspberry yellows. 



The raspberry disease mentioned is said to have been quite troublesome in 

 the vicinity of Loveland, the accompanying canes being small, brittle, discol- 

 ored, and the young shoots in the spring showing a decided tendency to turn 

 yellow and shrivel. A number of factors seem to be responsible for this condi- 

 tion, among them winter injury, spring freezing, and the presence of the fungus 

 Sphcerella ruhina. Spraying with Bordeaux mixtui-e for the control of the 

 fungus has been carried on with success. 



A revision of the North American species of Puccinia on Carex, F. D. Kern 

 and Mary A. Fitch {Ahs. in Science, n. sen, 35 {1912), No. 891, p. 150). — Notes 

 are given on about 25 species of Puccinia which can be recognized on Carex in 

 North America, the majority of them being endemic. About three-fifths of the 

 species have had their life histories worked out. 



Sclerotium rhizodes on Calamagrostis canadensis, A. B. Stout {Ahs. in 



Phytopathology, 1 {1911), No. 2, p. 69; Science, n. so:, 35 {1912), No. 892, p. 



200; Torreya, 12 {1912), No. 2, pp. Ji2, IfS). — A partial account is given of the 



'' author's investigations of the fungus 8. rhizodes, which has for its principal 



host plant C. canadensis. 



The fungus is coexistent in the leaves, buds, stems, rhizomes, and roots of 

 the infected plants. Filaments of the fungus were also found to form a thin 

 weft on the exterior of the roots and to extend out into the soil. The fungus 

 is shown to have a varying degree of parasitism in the different parts of the 

 host. On the leaves it is said to be vigorously parasitic. In the culms the 

 filaments are most abundant in the region of the nodes, but there is almost no 

 destruction of tissues. In the underground parts of the cuhns and in the 

 rhizomes Ihe hs^phfe completely digest the cell couteuts of cortical cells, t)ut 

 appear to have no effect on the cell walls except at the points of actual penetra- 

 tion. In the older portions of the roots the hyphte are scattered throughout the 

 cortex, where they occupy empty cells. In the younger lateral roots the fila- 

 ments of the fungus were found penetrating living cells and exhibiting charac- 

 teristics w^hich have been ascribed to mycorrhizal fungi. Ultimately, however, 

 the cell contents disappeared, while the fungus remained intact. 



The fungus is said to be perennial in the soil and in the underground por- 

 tions of the host. It is present in the buds, but is apparently unable to 

 penetrate into the growing apex. 



Infection experiments with powdery mildew of wheat, G. M. Reed {Ahs. in 

 Science, n. ser., 35 {1912), No. 891, p. 152).— The author reports experiments in 

 which 80 different varieties of Triticum, belonging to 9 different species, were 

 inoculated with couidia of Erysiphe graminis occurring on wheat. 



