502 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



groiuing on very dry soil ivith little icater-rctaininq properties should, if 

 possible, receive irrigation. 



" From observations made we are of opinion that the outbreak of the 

 Asparagus rust is of a sporadic nature, not likely to cause much harm in 

 the future provided attention is given to the production of vigorous plants." 



M. C. C. 



Parasitic Bacteria. 



Bacteria parasitic on Plants. By E. F. Smith {U.S.A. Dep. 



Agr. Division of Vegetable Pathology, Bull. No. 28 ; 1901). — Very few 

 diseases of plants have as yet been convincingly proved to be caused by 

 bacteria, and the author of this bulletin is one of the few workers who 

 aim at ascertaining definitely whether bacteria cause disease, or if they 

 only come to hasten the decay of plants already diseased. The size 

 (153 pp.) and the very detailed nature of the paper justify a better title 

 than a bulletin ; it is the result of a laborious bacteriological investiga- 

 tion on four species of yellow one-flagellate bacteria belonging to the 

 group Pseudomonas. The species selected for research are : — (1) Pseu- 

 domonas campestris (Pammel) occurring on Cabbage, Cauliflower, 

 Turnip, and other Cruciferte ; (2) Ps. phaseoli Smith, on Lima and 

 Bush Beans ; (3) Ps. hyacinthi Wakker, on Hyacinths ; (4) Ps. Stewarti 

 Smith, on Maize and Sweet Corn. The first species is probably the 

 cause of a disease observed for several years on Turnip and Cabbage in 

 Britain; it, aS well as the second (see Journal R.H.S., vol. xxvi., 1901, 

 p. 222) and third, has been proved by inoculation to cause disease in 

 healthy plants ; the fourth species is probably the cause of a disease on 

 Maize in the United States. The present paper deals with the behaviour 

 of the four species when studied by the methods of the bacteriologist, 

 and the greater part is occupied by description of the growth on solid 

 and fluid media, conditions of vitality, effects of temperature and sun- 

 light, formation of ferments, pigments and other by-products. The 

 details and results are indispensable to workers in this field. The 

 organisms are evidently allied, and the name " Yellow Pseudomonas group '* 

 is given. From the investigations a table of distinctions of these four 

 species has been drawn up, as well as a brief summary of the characters 

 they have in common. These bacteria are rod-like bodies, distinguished 

 in some phases of life by possessing a single polar flagellum ; at other 

 times they occur in short or long filaments, or in slimy masses. They 

 grow readily on many culture media, they require oxygen, are resistent to 

 dry air, and are destroyed by sunlight ; they live in the interior of plants, 

 and form a yellow or brownish slime. The paper concludes with a brief 

 review of some other yellow Pseudomonas species suspected to cause 

 disease in plants. — W. G. S. 



Bryophyta. 



Bryophyta, Notes on the Conductingr-tissue System in. By 



A. G. Tansley, M.A., and Edith Chick, B.Sc. {Ann. Bot. vol. xv., 

 No. Ivii. p. 1, 1901). — The Phanerogams and Pteridophytes (Flowering 

 plants, Ferns and Fern allies) possess a double conducting or vascular 



