JEHANGIR FARDUNJI DASTUR. 221 



Whatever affinity the inoculation experiments reveal between 

 the fungus under study and Pit. omnivora, Ph. omnivora, var. 

 AreccB and Ph. Faberi, the study of these fungi in pure cultures shows 

 very little in common between the first and the last three. Hartig 1 

 found oospores of Ph. Fagi in water cultures. His results have 

 been confirmed by de Bary' 2 and recently by Klebahn, 3 who studied 

 Ph. omnivora from beech seedlings in pure cultures, and by Himmel- 

 baur, 4 whose careful study of Ph. Fagi, the cultures of which were 

 supplied to him by Klebahn, and of Ph. cactorum have brought him 

 to the conclusion that these two species cannot be merged into each 

 other, under the common name of Ph. omnivora, as is done by de 

 Bary. He also got the oospores of Ph. cactorum 5 in water cultures. 

 Though I have worked with water cultures of castor Phi/tophthora 

 for months together I have never found the slightest trace of the 

 formation of oospores in these cultures. Klebahn also succeeded 

 in growing Ph. omnivora on sterilised potatoes and carrots, on which 

 media not only sporangia were formed but apparently oospores as 

 well. Ph. SyringcB has also produced oospores on carrots and 

 Coleman has found oospores of Ph. Faberi on sterilised potatoes. 

 The castor Phutophthora thus disagrees with these fungi by not grow- 

 ing on sterilised carrots and by producing on sterilised potatoes like 

 Ph. omnivora, var. Arecce only sterile mycelium and that too only when 

 inoculations were made on the cut surface or on the wounded rind. 

 Ph. omnivora, var. Arecce luxuriantly produced sporangia when 

 grown on sterilised flies and a rich sterile mycelium on boiled rice. 

 The castor Phykrphthora thus differs from this fungus in growing very 

 poorly on sterilised flies and producing sporangia and " resting " 

 conidia on boiled rice. 



The most important difference presented by the castor Phytoph- 

 t hora from these and all the other species of this genus, except Ph. 



1 Hartig, R. lor. ril., p. 4">. 



2 De Bary, A. Untersuchungen Liber die Peronosporeen and Saproiegrueen. Beitrage zui 

 Morph. and Physiol, der Pilze, 1881, p. 22. 



3 Klebahn, H. loc. cit., p. 71. 



* Himraelbaor, W. loc. cit., p, .">(:. 

 6 Ibid., p. 54. 



