12 
E. M. Cutting 
however, which we will now consider, have been regarded by Clinton 
as showing indications of the presence, amongst them, of physio¬ 
logical strains ( 16 ,17). 
This observer found in cultures of different species of Phyto- 
phthora an abundant formation of oospores, interpreted by him as 
hybrids, at the place of intersection of the hyphae. Murphy, working 
on Phytophthora erythroseptica , found a similar formation of oospores 
where neighbouring growths of hyphae met, and, at first, was inclined 
to think that he was dealing with a heterothallic form ( 35 ). Single 
hyphal cultures, however, were capable of fruiting alone when any 
check was made to the further growth of the fungus, as by cutting 
out a piece of the medium in the track of growth of the hyphae, 
oospore-formation immediately began. Murphy holds, therefore, 
that the phenomena observed by him was due to a nutritional check 
to the vegetative growth, initiating the sexual reproductive phase, 
and he thinks that Clinton’s results, mentioned above, can be 
explained in a similar way. 
Such interruptions do not necessarily induce an increased forma¬ 
tion of reproductive bodies amongst the fungi. 
Fitzpatrick has been investigating the origin of the binucleate 
condition in Eocronartium muscicola, a member of the Auricu- 
lariales; the germination of the uninucleate spores did not offer any 
solution, nor did an examination of its mycelium in one of the host 
plants give any further insight, as all the cells were binucleate ( 22 , 23 ). 
There were no clamp-connections, however, so that it was not pos¬ 
sible for migrations to take place there similar to those observed by 
Kniep in Corticium varians Kniep and C. serum Pers. The cross¬ 
walls of Eocronartium are provided with metachroma tic granules 
and in the large number of fungi, in which such granules are found 
so associated, it is also usual to find a pore in the cross-wall. It is 
possible that migrations in Eocronartium and similar Basidiomycetes 
may take place through such pores, as such migrations have been 
reported amongst the Ascomycetes(i8, 26 , 43 ). The only function that 
was widely accepted for the clamp-connections before this work of 
Kniep’s was that they facilitated the nutritive relations of the 
component cells of the hyphae. 
Kniep, it should be mentioned, has also found that a hypha after 
forming a basidium may go on growing and forming other basidia, 
in a manner which strikingly suggests a comparison with" the account 
of the ascal-formation in Pyronema, as given by Claussen; and, in 
fact, Kniep does hold that the ascus and basidium are homologous 
