Febeuaby 12, 1909] 



SCIENCE 



273 



Cross inoculations from forms on fruits seem 

 to indicate that the fungus may soon adapt itself 

 to a different host and after a few generations 

 develop about as readily on one fruit as another. 

 All are perhaps only slightly specialized physi- 

 ological forms of one omnivorous species. 

 A Bacterial Gall of the Daisy and its Relation 



to Gall Formatiotis on Other Plants: Dr. C. O. 



TowNSEND, Bureau of Plant Industry. 



In 1904 some Paris daisy plants affected with 

 galls of different sizes were received from a com- 

 mercial grower of this plant in New Jersey. 

 Work upon the cause of these gall formations and 

 their relation to similar abnormal growths upon 

 other plants was undertaken by the writer in 

 cooperation with Dr. Erwin P. Smith, in charge 

 of the Laboratory of Plant Pathology. Much of 

 the technical work in connection with the prob- 

 lems investigated has been performed by Miss 

 Nellie A. Brown, scientific assistant in the Labo- 

 ratory of Sugar Beet Investigations. 



After repeated efforts an organism was isolated 

 from the galls, which had the ability to induce 

 the formation of new galls upon healthy plants 

 when inoculated into the stems and branches or 

 even into the leaves of healthy daisy plants. 

 From these galls formed by inoculation, the organ- 

 ism has been isolated and the process of inocula- 

 tion repeated until no doubt remains regarding 

 the cause of the gall formations. 



The organism which produces these growths is 

 a short rod, motile, possessing from one to three 

 polar flagella, non-gas forming, and does not cloud 

 bouillon heavily. On agar plate cultures the col- 

 onies come up slowly, usually in from three to 

 five days, at a temperature of 25° C. The surface 

 colonies are translucent white, round, with entire 

 margins, smooth and dense. The growth is viscid 

 on agar streak cultures after three days. The 

 organism blues litmus milk, does not liquefy 

 gelatin and does not grow at blood temperature 

 in either agar or bouillon cultures. It will grow 

 slightly at a temperature below 0° C. 



The daisy organism will produce galls upon a 

 large number of other plants, including tomato, 

 potato, tobacco, sugar beet, hop, carnation, grape, 

 raspberry, peach and apple. This work has led 

 to the isolation of pathogenic Schizomycetes from 

 the galls of peach, hard gall of apple, hairy root 

 of apple, hop, rose and chestnut. The organisms 

 obtained from the galls of these different plants 

 are cross inoeulable and are very similar, if not 

 identical in size, shape, structure and habits of 

 growth on media with the organism from the 

 daisy gall. Pure cultures of these organisms are 



now under investigation. The abnormal growths 

 produced by inoculation with the organisms ob- 

 tained from the galls of the plants mentioned are 

 similar in many cases to those produced by the 

 daisy organism upon those plants. 



These investigations have left no doubt regard- 

 ing the cause of the crown gall of the peach and 

 at least some of the gall formations upon the 

 apple and other economic plants. 

 Variation of Fungi Due to Environment: Pro- 

 fessor F. L. Stevens and Mr. J. G. HAii, North 

 Carolina College of Agriculture and Mechanic 

 Arts. 



The effect of different densities of colonies on 

 a plate is reported for five species of -fungi, some 

 of which show an entire elimination of pycnidial 

 formation and the production of spores without 

 covering when plates are thickly sown. 



The effects of different densities of mycelium 

 upon zone formation are illustrated from Asoo- 

 ehyta and Solerotinia. 



The effects of chemicals as influencing the color, 

 growth and character of several species of fungi 

 are reported. The changes produced are often 

 suiiicient to shift the fungus from one order to 

 another. 



The effect of light upon growth, spore forma- 

 tion and zonation of colonies, of several species 

 of fungi is reported. 



Under the heading of " unknown factors " sev- 

 eral changes of character which could not be 

 attributed to environment are mentioned. 



Duncan S. Johnson, 



Johns Hopkins Univeksitt 



THE ASSOCIATION OF AMERICAN 

 GEOGRAPHERS 



The fifth annual meeting was held in Balti- 

 more, December 31, 1908, to January 2, 1909, 

 under the presidency of Mr. G. K. Gilbert. Pro- 

 fessor Albrecht Penck gave a lecture before the 

 association at its opening session on Thursday 

 evening, on " Man, Soil and Climate." Other fea- 

 tures of the meeting were: the president's address 

 by Mr. Gilbert, on the subject " Earthquake Fore- 

 casts," and a round table conference on " Geog- 

 raphy for Secondary Schools," conducted by Pro- 

 fessor R. E. Dodge. The conference was held 

 informally in connection with a smoker at the 

 Johns Hopkins Club on Friday evening. About 

 thirty papers were read by members, representing 

 meteorology and various phases of physiographic, 

 biological, human and educational geography. 



