1919 J AGRICULTURAL BOTANY. ^ 523 



of the ground are given with suggestions or explanations regarding tlie proc- 

 esses involved. 



Cross-inoculation of legumes, G. P. Koch and J. R. Bftler (F^oil Sci., 6 

 (1018), No. 5, pp. 397-403). — Reporting data from cross-inoculation tests dealing 

 with several common legumes, the authors state that Bacillus radicicola iso- 

 lated from roots of alfalfa, sweet clover, and bur clover all cross-inoculated, 

 although but slight infection followed inoculation of bur clover (roots) with 

 organisms from alfalfa and sweet clover. Organisms from either red, white, 

 crimson, or alsike clover inoculated upon any other of these showed normal 

 vigor. Cross-inoculation succeeded (showing a diHereuce in vigor, however) 

 between vetch, sweet pea, garden pea, and Canada field pea. In nearly all 

 cases organisms from the cowpea group cross-inoculated successfully. 



Potassium requirements of bacteria, G. P. Koch {Soil Sci., 5 (191S), No. 3, 

 pp. 219-224) .—This information has already been noted (E. S. R.. 39, p. 619). 



On the occurrence, behavior, and origin of a smooth-stemmed form of the 

 common foxglove (Digitalis purpurea), E. R. SArxDERs {Jour. Genetics, 7 

 (191S), Ko. 3, pp. 215-228). — The author has continued through several genera- 

 tions a study of some peculiarities observed in work previously noted (E. S. 

 R., 25, p. 229). She states that besides the form which is now considered 

 as the type D. purpurea puheseens another form exists and this is designated 

 as D. purpurea nudicauUs. This resembles the type in all but surface charac- 

 ters, which are described with a discussion of their possible significance. 



The purple hyacinth bean, G. F. FEEEirAN {Bat. Gaz., 66 {WIS), No. 6, pp. 

 512-523, Jigs. 7). — Concluding his presentation and discussion of opinion and 

 evidence, the author sustains the designation by Linnaeus of the common an- 

 nual (in the tropics perennial) hyacinth bean as Dolichos lahlah, and the more 

 slender climber (in northern climates perennial) as D. lignosiis. 



The effect of certain organic substances on seed germination, E. B. Fred 

 (Soil Sci., 6 {1918), No. 5, pp. 333-349, figs. iO).— Experiments conducted at the 

 Wisconsin Experiment Station, in which alfalfa, casein, peptone, and sugar 

 were added in varying amounts to silt loam soil in which alfalfa, buckwheat, 

 castor bean, red clover, corn, cotton, flax, hemp, white lupine, mustard, oats, 

 serradella, soy bean, sunflower, sweet pea, and wheat seeds were planted, are 

 reported. 



It was found that nitrogenous substances such as alfalfa powder, casein, 

 and peptone did not seriously injure seed germination unless used in very 

 large quantities. As compared with green manure (nitrogen content), very 

 large amounts of casein and peptone were required to cause a noticeable de- 

 crease in germination. Calcium carbonate apparently did not lessen the de- 

 crease in germination due to very large applications of alfalfa powder or 

 casein. Sugar greatly increased bacterial growth and retarded the rate of 

 seed germination. In large amounts it decreased the percentage of germina- 

 tion. Soil sterilization often inhibited the rate of seed germination. 



Difference in the action of radium on green plants in the presence and ab- 

 sence of light, C. Packard {.Jour. Gen. PJu/sioL, 1 {1918), No. 1. pp. 37, 38). — 

 Tests carried out with Spirogyra and Volvox exposed to radioactivity are said 

 to have shown that the life of the cell is longer under such exposure in light 

 than in darkness, being prolonged apparently by some condition connected with 

 photosynthesis. 



On the dynamics of photosynthesis, W. J. V. Osterhottt and A. R. 0. Haas 

 (Jour: Gen. Physiol., 1 (1918), No. 1, pp. 1-16, figs. 5). — The authors describe 

 (with a discussion of results) a study of sea lettuce (XJlva rlgida) 

 carried on during August in order to obtain data for the study of the dynamics 

 of photosynthesis. They have developed a method of investigation based on the 



