224 PHYTOPHTHORA PARASITICA. 



Ph. Faberi not only shows points of disagreement in inoculation 

 experiments and in its growth on artificial media but also in its 

 oospores. Both von Faber and Coleman consider them to be 

 parthogenetic, as they failed to find antheridia ; but Rorer 1 has 

 found them as his figure (Plate XVIII, Fig. 14), distinctly shows the 

 presence of an antheridium. He has also found chlamydospores, 

 which neither of the former investigators seem to have found. Per- 

 haps as already stated they have mistaken these chlamydospores for 

 parthogenetic oospores. According to von Faber the oospores measure 

 45/u in diameter, while Coleman says they are 22-45m in diameter. 

 Rorer measures them between 38 and 40m and the chlamydospores 

 between 30 and 50m. Whichever of these measurements are correct, 

 they show that the oospores are much bigger than those of the 

 castor Phytophthora. 



Apart from the already noted differences that exist between Ph. 

 Syringce and our Phytophthora there are also those of sporangia and 

 oospores. The sporangia of Ph. Syringce, unlike those of the other 

 species of the genus, have flat lid -like papillae instead of raised semi- 

 globular papilla?. The oospores are yellowish and much bigger. 

 According to Himmelbaur they are 30m in diameter and according to 

 Klebahn 18-30 x 17-25m. 



As we have seen Ph. Phaseoli perhaps offers some resemblance in 

 the mode of the development of its oospores to the Phytophthora on 

 castor. But a study of these two species leaves no doubt as to their 

 being quite different from each other. The mycelium of the Ameri- 

 can fungus 2 is only intercellular ; the hyphse emerge singly or 

 several in a cluster solely through stomata ; the conidiphores are 

 simple or, unlike its Indian ally, more commonly branched at the 

 base ; they measure 300-475m in length ; while those of Phytoph- 

 thora on castor measure, as a rule, 100-300.U. Again the former have 

 on them half a dozen or more nodulose swellings which show the 

 points of attachment of sporangia and the sporangia measure 

 17-35 x 28-42/x. These swellings have never been found on the coni- 



l Rorer, J. B. loc. cit. 



% Thaxter, R, A new American Phytophthora. Bot. Gaz. XIV, No. 11, 1889 r p. 273, 



