nrSKASl'.S Ol-' I'l.ANT^^. 45 



sijiltc (/nniiiiiis). A coiisidcnil)!!' collcclioii oL" varieties (if wlicat and liaiicy 

 was olitaliicd and various grades df resistance were estahlisiied liy eressiiiLr the 

 resistant and suseejitihle vai-ieties. The liyhridiziii!; was done in 1!I04 and tlie 

 results rei)orted were observed dnriiii,' their .growth in 1!K)4 and WOr>. 



The results showed that erossins^ immune and susee;)til)le varieties yielded 

 offsprings suseeptihle to disease. Upon self-fertilization of these susceptil)le 

 individuals, inunune and suseeptible descendants in a proportion of 1 of the 

 forniei- to ."> of the latter were secured. Where the degree of sui^ceptibility 

 differed in the two parents, the hybrid resembled the more susceptible parent 

 in that respect. The relatively innnune forms breed true to this characteristic 

 in the succeeding generations, in all expei-inients the degree of susceptibility 

 was found to be variable. Innnnnity ajipears to be independent of any discern- 

 iiile morphological character, and it is entirely practicable to breed varieties 

 ni()ri)hologically similar To one another but imnuine or susceptible to parasitic 

 fungi. 



A contribution to the biology of phanerogamic parasites, A. Fraysse 

 (Rei: Gen. Bot.. J!) (lUOl), A o. 2 IS. pji. ',l>-(iU, fji/.s. 13).— The author presents 

 a re.sume of bis more extended work," giving the results of bis observations 

 and experiments with a considerable numl>er of phanerogamic parasites. The 

 general biolog.v of the parasites is described, after which their physiology is 

 discussed. 



In the species studied, tlie author^ found that the parasites attack the roots of 

 the host plants by means of haustoria. and tliey are apparently limited to those 

 hosts which offer large reserves of carbon compounds, such as are found in 

 plants possessing bacterial tubercles, uiycorrhiza, starch cysts, etc. The number 

 of haustoria seems to be limited by the host plant, but their form and duration 

 are determined by the necessities of the parasite. The haustoria are believed 

 to re])resent modified roots which are adapted to the purposes of absorption 

 through their iieculiar mechanism. 



In some chloroi)hyll-l»earing species the parasite takes from the host only a 

 p(trtion of its mineral and organic carbon, while in others practically all of the 

 organic r-arbon is received from the host plant. As a result of his experimenis 

 the author claims that glucose is the principal source of carbon taken up l)y 

 the parasites, and that while starch is abund.-ait in the host it is transformed 

 into sugar by the diastases. 



The haustoria are said to force their way into the host plant through the 

 action of certain diastases, the most connnon of which is cellulase. 



Bacterial diseases of fruits and vegetables, S. F. Edwards (A«». Rpf. Oii- 

 Uirio Apr. Col. aiid E.rpt. Farm, 32 {1906), pp. 1.36, 137. — Observations are 

 given of the bacterial diseases of fruits and vegetables which are noted as 

 occurring during the season covered b.v the report. 



The organism causing the black rot of cabbages and allied plants was found 

 affecting kale, collards. Brtissels sprouts, several varieties of cabbage, broccoli, 

 <-auliflower. kohl-rabi, ruta-bagas, and turnips. Some varieties of these vege- 

 tables were n)ore severely injiu-ed than others. 



The bacterial blight of the ijear. (juince, and apple continues to be destriic- 

 tive in Ontario and it was observed in the iiast season on ornamental varieties 

 of the English hawthorn. This variety which is characterized by its double 

 scarlet flowers had been planted as an ornamental quite extensively, but in 

 .Inly of the past season it was found to be affected by a blight. A study of 



" Contrilmtion a la biologie des plantes phaiieroganies para.'^ites. Thesis. 

 Paris, lOdC. ji]). ISO. figs. .^.1. 



