NOTES AND ABSTRACTS. 



455 



annually, rotting away at the end of the growing season, the rot kill- 

 ing the adjacent tissues and cutting off the circulation of the vine, 

 having much the effect of a canker. ' Muscat of Alexandria ' and 

 ' Mission ' were found among the most susceptible varieties of vine, 

 but none were found to be entirely immune. Some, however, possess 

 a high degree of resistance, especially * Eupestris St. George' and 

 'Lenoir.' Among others, * Feher Szagos,' 'Sweetwater,' 'Seedless 

 Sultana,' ' Carignane,' * Grenache/ ' Gros Colman,' * Mataro, ' * Black 

 Malvoisie, ' and ' Burger ' have been found more or less resistant on 

 their own roots in Mexico, and with the first two mentioned are recom- 

 mended for planting in infected vineyards. 



The disease is communicated by water of irrigation, by cuttings from 

 diseased plants, probably by the pruning knife, and by insects. It is 

 recommended that cuttings and young vines should be planted deeply 

 to avoid injury from frost, and that plants should be propagated under 

 the supervision of the grower. The time of pruning should be either 

 before or just after the period of sap flow, and winter protection from 

 frost should be given, — F. J. C. 



Crown-g-all, The relation of, to Legrume Inoculation. By 



K. F. Kellerman (U.S.A. Dept. Agr., Bur. PI Ind., Circ. 76; March 

 1911). — This circular points out the characters that distinguish the 

 nodules produced by nitrogen-fixing bacteria on the roots of clover and 

 lucerne from those produced by Bacillus iumefaciens, the crown gall 

 organism. The * nitrogen-fixing nodules ' are outgrowths from the 

 root, and have no more apparent effect upon the root than an ordinary 

 branch ; the interior contains flesh-coloured cells full of bacteria, which 

 may easily be seen under the microscope. The crown-gall tumour 

 causes much distortion of the root, and frequently the production of 

 branches from the tumour itself ; the interior of the tumour is white, 

 and it is difficult to demonstrate bacteria in the cells, even with the 

 most careful preparation. 



In the laboratory the nodule bacteria are found not to absorb colour 

 from agar coloured with Congo-red as do the crown-gall organisms, and 

 the latter produce nitrite in media containing nitrate, which the former 

 do not. 



The fact that leguminous plants act as hosts for the crown-gall 

 organism may be of economic importance when sugar-beets or orchard 

 trees follow on the same soil. — F. J. C. 



Cymbidium insig"ne. By F. Ledien (Orchis, vol. V. pt. 4, 

 pp. 51-52 ; 1 plate). — Gymhidium insigne is found on grassy slopes in 

 South Annam at an altitude of 5,000 feet. The long flower stems 

 bear 15 to 20 flowers from December to January. This orchid must 

 be treated like an Odontoglossum in summer. — S. E. W. 



Dahlia imperialis. By S. Mottet (Rev. Hort., Feb. 1, 1911, 

 pp. 61-63 ; 2 illus.). — This dahlia, which assumes the form of a robust 

 shrub 12 or 14 feet high, bearing an abundant inflorescence of large 



