BUTLER AND KULKARNI. 255 



All the inoculations failed except those on seedlings of Gilia, 

 where they succeeded well, and on wounded leaves of potato and 

 tomato. The potato infection was definite, that of tomato less so, 

 as little spreading took place. The controls remained healthy 

 in every case. It is clear that the present fungus is restricted in 

 its choice of hosts and therefore more highly specialised than species 

 such as omnivora and its allies. 



A few tests were made to determine whether temperature had 

 any effect on the infection of seedlings. Seedlings of Gilia, Clarkia, 

 CEnothera and Fagopyrum were used. Small pots containing the 

 seedlings were placed in the cool incubator at 25°C, others being 

 kept in the laboratory, the temperature of which at the time was 

 just over 30°C. Both sets were inoculated with swimming zoo- 

 spores, which at the former temperature are formed freely but at 

 the latter only if sown in chilled water. The Gilia seedlings were 

 attacked both in the cold and warm pots. CEnothera and Clarkia 

 remained healthy in both. Fagopyrum was attacked at the 

 cotyledon of one seedling only, in the cool incubator, but not at 

 all in the warm pot. Temperature variations within the limits 

 which markedly affect zoospore formation, have therefore little 

 influence on the resistance of seedlings of the species tried, to 

 Phytophthora Colocasice. 



V. Systematic position of Phytophthora Colocasle. 



Raciborski (J.c.p. 10) noted that this species appeared to be 

 most closely allied to Ph. Phaseoli Thaxt. which it resembles in the 

 size of the sporangia while differing in the characters of the stalk. 

 With Ph. omnivora de Bary it agrees in the small number of 

 sporangia formed on each sporangiophore. It is quite different 

 from Ph. Nicotiancs Breda de Haan. 



Sawada {I.e. p. 1) transferred it to the genus Kawakamia as 

 K. Colocasice (Rac.) Sawada. Kawakamia is defined by Miyabe 1 as 

 parasitic, without haustoria, with conidiophores emerging from the 



1 Miyabe, Kingo, in Kawakami, T. " Kawakamia. a new genus belonging to the Perano- 

 sporaccce," Tokyo, Shokwabo & Co., 190-4. 



