726 



Journal of Agricultural Research 



Vol. XX, No. 9 



Group V: Mycelium gray to black, rather fluffy; no pink spore masses 

 on any medium; spore production scant and on some media no spores 

 produced. 



Since the cultural characteristics of some strains changed, it became 

 necessary to reclassify the different strains on the following dates: Janu- 

 ary 27, 1917; April 16, 1917; September 13, 1917; and February 28, 

 19 18. Very few of the strains remained in the group in which they were 

 placed at the first classification. Under artificial cultivation the charac- 

 teristics of the various strains changed; therefore, they were placed in 

 different groups (see Table I). There were only three strains whose 

 characteristics remained constant in group I. In group II there was 

 only one strain which remained constant. It will be noticed that in 

 group IV cultures 296 and 299 remained constant until September 13, 

 19 17. At the next date of classification these two strains were placed 

 in group II. No strains were placed in group V until September 13, 

 19 17. This may be due to the fact that under artificial conditions these 

 strains lost their power to produce spores. 



Table I. — Classification of strains of Colletotrichum gloeosporioides into groups 



<* Culture remained in its original class throughout the work. 



VARIATIONS IN SPORE LENGTH 



Since such great differences were found in cultural characteristics be- 

 tween the strains, the question arose whether differences could be found 

 in the spore length of the various strains. One hundred spores were 

 measured from each strain. The measurements were made in the fol- 



