FOOT-ROT DISEASES OF WHEAT IN AMERICA 9 
pathologists over the world continued to designate the take-ail 
fungus 0. graminis. 
Fitzpatrick, homas, and Kirby (2) inquired into this subject. 
They concluded that Berlese was in error concerning the identity of 
Ophiobolus eucryptus with O. caricett and O. graminis and held that 
the take-all fungus should be designated O. caricet?. In going over 
the evidence presented by these workers it is found that “they were 
unable to obtain mature ascus-bearing type material of any of the 
three species under discussion. They did study specimens of O. 
eucryptus on iris, an entirely different host plant from the original, 
and found the asci and ascospores to be different from those of the 
take-all fungus they were studying. As to O. cariceti, they base 
their identification of this on material in Cooke’s herbarium col- 
lected by Broome but clearly not part of the type collection, and it 
is doubtful whether Broome even identified the fungus on this ma- 
terial, as evidenced by Wakefield’s letter published by Fitzpatrick 
and his collaborators (2/). 
From the evidence presented by Fitzpatrick, Thomas, and Kirby 
it seems reasonable to believe that no ascus-bearing type specimens 
of Ophiobolus eucryptus and O. cariceti are now in existence, but the 
original descriptions and figures (5, 6) may be taken to represent 
them. Reference to these descriptions and drawings shows that O. 
cariceti is described with ascospores measuring 0.003 to 0.004 inch 
(76.2 to 101.6 microns) in length, whereas O. eucryptus is described 
with ascospores measuring 1/500 inch (50.8 microns) in length, thus 
clearly showing that two distinct species are.involved. In view of 
the wide difference between the spore lengths given in these original 
descriptions it is difficult to understand the interpretation of Berlese 
(7) that the two species are identical. It is possible that he com- 
mitted an error when he compared the types of these species, as was | 
pointed out by Hitzpatrick, Thomas, and Kirby, but if he did it 
seems quite clear that his comparison between the type materials of 
O. cariceti and QO. graminis should also be looked upon with doubt 
and certainly should not be considered as a basis for a change in the 
nomenclature of the take-all fungus, as was done by Fitzpatrick and 
his collaborators. 
It is also possible that Berkeley and Broome described their ma- 
terial inaccurately, but in the absence of the type specimens it is im- 
possible to determine this point, and it therefore seems quite clear 
that Ophiobolus eucry ptus and O. cariceti can not now be considered 
identical. 
As to the identity of Ophiobolus graminis with the other two 
species under discussion at present it is only possible to compare the 
published descriptions. A study of the type material of O. graminis, 
which is presumably in existence, might throw some light on the 
matter, but this seems doubtful, because all of the take-all fungus 
which has been described by var ious workers has essentially answ ered 
Saccardo’s description of O. graminis. This fungus is described as 
having ascospores measuring 70 to 75 microns in length and 3 
microns in width. Clearly this length dimension falls between those 
for O.eucrypius and O. cariceti. ‘As the exact widths were not re- 
corded for the last mentioned species, this can not be used as a means 
of comparison. 
44918°—25——2 
