A Dry Rot of the Irish Potato Tuber 
47 
For Fusarium orthoceras. 
0- septate 92 per cent. 
1- septate 5 per cent. 
2- septate Few. 
3- septate 3 per cent. 
4- 5-septate Few. 
For Fusarium tuberivorum, culture 150 days old. 
0- septate Few. 
1- septate 98 per cent. 
2+- septate Very few. 
SUMMARY. 
We have in Fusarium tuberivorum an interesting organism, 
both from a morphological and from a physiological point of view. 
If we consider all species of Fusarium as belonging together, we 
can look upon Fusarium orthoceras either as the farthest away 
from its ascomycete ally, if there is any, or as nearest to it If 
the contentions that some of the species of Fusarium have 
been connected with certain Nectria will hold, or that Neocos- 
mospora is closely related, it is apparent that such related 
species of Fusarium are characterized by the presence of several- 
septate curved spores. Then such a form as Fusarium orthoceras 
would have to be considered the most remote relative. It is 
possible of course that Fusarium is such a Babel as the genus 
Gloeosporium and that it is a sort of rendezvous for the ends 
of several ascomycete forms. If the latter is the case it will be 
almost useless to try to combine the Fusarium species into a 
coherent assemblage. On the other hand, if they are related it 
will be necessary to link only one of these species to an asco- 
mycete form to give all of them their proper place. It is a per- 
plexing state of affairs, however, that the Ascomycetes to which 
the Fusarium species have often been referred are themselves in 
about as orderly a state as the Fusarium spcies are. 
No matter whether we adopt one or the other view, it seems 
quite safe to say that Fusarium tuberivorum shows nicely the 
transitions by which such forms as Fusarium orthoceras and 
Fusarium solani or Fusarium theobromae can be connected. 
Especially is this true since the characters which appear under 
normal conditions in this fungus can be varied considerably by 
changing the environment. 
Fusarium orthoceras normally shows a preponderating num- 
ber of non-septate conidia and only a few 3-septate conidia. The 
spores are not curved and show no decided differentiation of 
apical and basal cells. Fusarium snJani ordinarily shows the 
