180 Scientific Proceedings, Royal Dublin Society. 



particular, in a further paper^ published coincidently with it, revealed the 

 fact that, judging from the final state of affairs, the course of development 

 of the sexual organs in P. infestans de Bary and in P. Pliaseoli Thast. 

 is similar to the peculiar one discovered for P. enjthroseptica. It was 

 further surmised that in all probability the development of these organs in 

 P. omnivora var. Arecae Coleman follows an identical course. 



On the other hand, it was found that the development of these organs 

 in certain other members of the genus, such as P. Cactorum Schroet., P. Fagi 

 Hart., and P. Si/ringae Kleb., was of the ordinary type in which an out- 

 growth from the antheridium penetrates the oogonium laterally, and thus 

 effects the fertilization of the oosphere. 



It was therefore suggested that the generic name Phytophthora should 

 be reserved for those species (viz. erythrofieptica infestans, Pliaseoli, and 

 probably omnivora var. Arecae) having the newly discovered mode of develop- 

 ment of their sexual organs, and that those species which follow the omnivora ^ 

 or Cactorum type should be assembled in a new genus — Nozemia. 



Shortly after the publication of the papers referred to further proof of 

 the existence of such a novel mode of development of the sexual organs was 

 adduced in the case of two other members of the genus occurring in India by 

 Dastur^ and by Butler and Kulkarni.' Dastur describes the development as 

 it occurs in a new species (P. parasitica) which he had discovered as the cause 

 of a disease in the Castor Oil plant ; while Butler and Kulkarni deal with the 

 Colocasia disease caused by P. Golocasiae (a species originally described by 

 Eaeiborski, to whom the sexual organs were unknown), and show that the 

 mode of development of the sexual organs here is similar to that which occurs 

 in P. parasitica. 



In all essential points the course of development of these organs in 

 P. parasitica and P. Golocasiae is similar to that already described as occurring 

 in P. erythroseptica.'^ Of the three species, P. parasitica appears to stand alone 



1 Pethybridge, Gr. H., and P. A. Murphy : " On Pure Cultures of Fhylophthora infestans de Bary, 

 and the Development of Oospores." Soi. Proc. Eoy. Dublin Soc, vol. xiii(N'.S), No. 36, March, 

 1913. 



^ Dastm-, J. F. : "On Phytophthora parasitica nov. spec. A new disease of the Castor Oil Plant." 

 Mem. Dept. Agric, India. Bot. Ser., vol. v, No. 4, May, 1913. 



^ Butler, E. J., and G. S. Kulkarni: " Studies in Peronosporaceae. Colocasia Blight caused by 

 Phytophthora Golocasiae Eac." Mem. Dep. Agric, India. Bot. Ser., vol. v, No. 5, May, 1913. 



* Massee, in his recently published " Mildews, Rusts, and Smuts," London, 1913, in referring, 

 on p. 206, to the apparent uniqueness amongst fungi of the mode of development of the oospore in 

 P. erythroseptica, makes use, for some not very intelligible reason, of the expression, " Long may it 

 remain so." Although the fact that I showed that both F. Phaseoli and P. infestans conform to the 

 erythroseptica type in this respect, failed to have the effect of strangling this curious aspiration at its 

 birth, perhaps the published observations on P. parasitica and P. Golocasiae here alluded to will be 

 adequate to provide the ootip de grdce for it while still in its infancy. 



