Fusaria of Potatoes 201 



On hard lima-bean agar, culture ten days old; conidia from pseudopion- 

 notes : 

 Conidia: 0-septate, rare 



1-septate, 5 per cent 



2-septate, rare 



3-septate, 15 per cent 



4-septate, 10 per cent 



5-septate, 70 per cent, 43 x 4.1 (35-50 x 3.8-4.7) M 



In some cases 5-septate conidia were up to 100 per cent, in others 

 conidia of lower septation were as high as 50 per cent. Of the smaller, 

 3-septate conidia were dominant. 



On rye straw, culture fifty days old; conidia from aerial mycelium close 

 to substratum: 

 Conidia: 3-septate, 10 per cent 



4-septate, 5 per cent 



5-septate, 85 per cent, 31.25 x 4.1 (27-36 x 3.9-4.6)m 



Average of the above measurements : 

 Conidia: 0-septate, rare 



1-septate, 2 per cent 

 2-septate, 1.5 per cent 

 3-septate, 21 per cent, 33 x 3.75/z 

 4-septate, 15 per cent 

 5-septate, 60.5 per cent, 42 x 4.3ju 

 6- to 8-septate, very rare, 58 x 4.7/z 



32. Fusarium bullatum var. roseum n. var. (Fig. 28; PI. m, fig. 2) 



Differs from F. bullatum mainly by its red substratum (on agar rich in 

 glucose, see Plate in, figure 2) and by higher septation of conidia. 



Hab. Same as that of F. bullatum. 



This organism and F. bullatum are in general, especially in minute 

 details of the character of the mycelium and in the chlamydospores, 

 very much alike, and both were isolated from the same planting of diseased 

 tissue of a rotted potato tuber and separated out on the first dilution. 

 It is possible that they represent an example of a sudden and permanent 

 variation of one Fusarium in pure culture. 



