JEHANGIR FARDUNJI DASTUR. 225 



diophores of the latter as they bear only single terminal sporangia 

 which are bigger. The antheridia 1 differ from those of the castor 

 Phytophthora in being temporary ; the oogonia are much bigger, as 

 they measure 23-38m in diameter and loosely envelope the oospores, 

 which measure 26-28m in diameter and possess a thicker wall. In 

 corn meal juice agar, Clinton 2 found practically no aerial growth but 

 a slight embedded growth in which oospores were developed. But 

 our fungus formed a fairly good aerial growth producing sporangia. 

 Oospores were never developed in this medium. Again in corn- 

 meal there was practically no growth, but on this medium the 

 castor Phijtophthora gave a copious aerial growth. 



Ph. Thalictri, which Clinton 3 suspects to be identical with 

 Ph. Phaseoli, differs from our fungus in having larger and branched 

 conidiophores, smaller sporangia and bigger and more thick-walled 

 oospores, which do not differ materially from those of Ph. Phaseoli. 

 The oogonia measure 25-33/*, are reddish brown and loosely envelope 

 the oospores, which have 3-4/x thick walls and are 18'5-25m in 

 diameter. 



Ph. infestans presents no point of agreement : the sporangio- 

 phores are branched and nodulose, the sporangia are smaller (27-30 x 

 15-20/*) and the oogonia and oospores much bigger (34-50/* and 24-35/< 

 respectively). 



There is absolutely no relationship between the Phytophthora 

 on castor or Ph. Colocasicr, and Pit. Nicotiance, as apart from 

 morphological differences, the castor Phytophthora failed to in- 

 oculate tobacco seedlings and Colocasia antiquarian and the parasite 

 of the latter did not cross-inoculate seedlings and plants of 

 castor. 



It is clear from all that has been said above that the Phytopkthora 

 on castor is quite different from the known species of this genus. 

 I therefore propose to name it Ph. parasitica nov. spec. 



1 Clinton, G. P. loc. cit., 1905, p. 293. 



2 Ibid., loc. cit., 1907-190$, p. 905. 



3 Ibid., p. S94. 



