2IO MAINE AGRICUI^TURAI, EXPERIMENT STATION. I913. 



2-celled. Very frequently in cultures 2 to 4 weeks old the spores 

 of the obovate type in this fungus are about equal in number to 

 those of the septate Fusarium type while in the same cultures 

 when a few days old a much smaller proportion of obovate 

 spores is found. This is especially striking when the spores are 

 sown in prune agar plates. The young colonies begin to produce 

 spores of the septate Fusarium type in 3 to 4 days but if the 

 cultures are allowed to continue their growth for 3 to 4 weeks 

 large number of spores of the obovate type are produced. Figs. 

 89 to 93 show the different forms of spores which are found 

 in cultures of this fungus, F II and F IV being strains of 

 the same fungus. The obovate spores are as a rule about 8 

 microns in diameter, the septate vary from ii to 41 microns 

 in length and from 2.75 to 5.5 in width. They are one to 

 5-septate and may be straight or curved. According to the 

 system of Appel and V/ollenweber the spores which occur in 

 the young cultures on agar are to be regarded as abnormal. 



The first thought to occur on finding spores of the obovate 

 and pyriform types in cultures which in other respect are so 

 strikingly similar to typical cultures of Fusarium is that the 

 cultures must not be pure. Plating out and starting from colo- 

 nies which had developed from single spores gave cultures which 

 produced the diff'erent types of spores. Moreover, it is possible 

 to find spores of the long type and of the obovate type cut off 

 from the same conidiophore so that one is forced to the con- 

 clusion that the extremely different forms belong to the same 

 fungus. 



In the first examinations of fungi of the type of F II found 

 in connection with studies of decaying apples, the writer felt 

 no hesitancy in referring the fungus to that genus on account of 

 its striking similarity to other species of the genus. Later when 

 it was found that the obovate, pyriform, and septate spores 

 belonged to the same fungus the question of its proper classi- 

 fication became more difficult. Of the many species of Fusa- 

 rium, the waiter found none which was described as producing 

 spores of such a strikingly obovate form. However, it is to be 

 remembered that only a comparatively small number of the 

 species of Fusarium were described from material which had 

 been under observation in culture for a long enough time that 

 all of the spore forms could be taken into consideration. For 



