BUTLER AND KULKARNI. 257 



and that he was not certain that this does not sometimes occur. 

 The sexual organs themselves approach those of Ph. Colocasice 

 closely in measurements. So also the absence of branching in the 

 conidiophores is a point of resemblance. But the characters of 

 the external growth on the host differ considerably, that of Ph. 

 Phaseoli being conspicuous and forming a white felt on the pods 

 while the Colocasia fungus is with difficulty visible to the naked 

 eye. The conidiophores of the former are also many times longer 

 than those of the latter and they produce several sporangia suc- 

 cessively, the stalk continuing its growth by a new branch just 

 below the spore, whereas on Colocasia usually only one spore is 

 borne on each stalk. The sporangia are shorter in Ph. Phaseoli 

 and the basal stalk left attached to the spore, when it is shed, is 

 less distinct. These differences are enough to separate the two 

 species. 



From the other species of Phytophthora with sexual spores 

 resembling ours, Ph. "parasitica Dastur is at once separated by its 

 broader sporangia, longer conidiophores and smaller oospores. 

 Inoculation experiments also show that its range of hosts is very 

 much wider. In the group of forms formerly included as Ph. 

 omnivora de Bary, two require consideration as having possibly a 

 similar type of development of the sexual organs to our species. 

 These are Ph. Fagi as described by Himmelbaur 1 and Ph. omnivora 

 var. Arecce Coleman. Ph. Fagi as first described by Hartio- 2 

 was figured with the antheridium sometimes arising on a distinct 

 hypha and attached to the oogonium at some distance from its 

 base, sometimes on the same stalk and closely applied to the base, 

 so that the oogonium appears to arise directly from the anthe- 

 ridium itself (Hartig I.e. p. 49 and Taf. Ill, fig. 24 b.). Himmelbaur 

 states that the antheridium is attached to the underside of the 

 oogonium, near its base. It appears probable that a penetration 

 of the antheridium by the oogonial stalk sometimes occurs in 



1 Himmelbaur, W. Zur Kenntnis der Phytophthoreen. Jahrb. d. Hamburg Wissensch. 

 Anstalten, XXVIII, 1910. 



■ Hartig, R. Der Buchenkeimlingspilz, Phylophthora Fagi. Unters a. d. forstbotan. 



Iusl. z. Miinchen, I, 1880. 



