W. MCRAE 



253 



measured, and it may be that some of them were not fully mature. As the 

 case stands at present, it appears that oogonia and oospores in culture in 

 French-bean-aijar are somewhat larger than those iti fruits. 



Summary" of the Mt^AsaREMENTS of oogonia an^d oospores. 

 In culture. 



The position of the antheridium puts this Phytophthora into the infkstans 

 group as constituted by Pethybridge, the members of which now are P. eryth- 

 rosepticn Pethyb., P. infestans deBary, P. Phaseoli Thaxt., P. parasitica Dast., 

 P. ColocasicB Racib., P. Allii K. Sawada, P. MelongencB K. Sawada, and probably 

 also P. arecm (Col era.) Pethyb., and P. Thalictri Wilson and Davis. It 

 differs from P. erythroseptica in the larger size of the sporangia, in the presence 

 of an apical papilla on the sporangium, and in the readiness with which it 

 discharges zoospores. The oogonium and oospore are more variable, the 

 oospore-wall is thicker and the colour is more marked. It diiTers from 

 P. infestans in the larger and more elongated sporangia, in the smaller 

 antheridia, in the slightly smaller oogonia and oospores, and in the fact that 

 the oogonial-wall is not brittle, pressure "on the cover slip not causing the 

 oospore to be^expelled. It differs from P. PhaseoU in that the conidiophores 

 are not tapering, and do not have swollen nodes, and in the larger sporangia 

 and oogonia. It differs from P. parasitica in the more elongated sporangia, 

 larger oogonia, and oospores, q,nd in the absence of chlamydospores. It differs 



