320 NINETEENTH REPORT. 



It is noteworthy tliat alsike clover is far more resistant to most of the 

 common diseases tlian is red clover. The possibility of hybridizing red 

 and alsike clover in order to produce a disease resistant strain suggests 

 itself. Certain cultural characters of alsike clover, as for example, the 

 abilitj' to grow upon "clover-sick" soil, might also be contributed to the 

 improvement of the red clover strain. 



SUMMARY. 



The disease caused by M. sarcinaeforme lias so far not been carefully 

 investigated. It is widely distributed in the United States and Europe. 

 The loss it causes has not been estimated, but it has been responsible 

 for local damage in various parts of the United States. 



The fungus affects both the leaves and petioles, — on the former caus- 

 ing a typical concentrically marked leaf spot, on the latter brown to 

 black linear streaks. The casual relation of the fungus M. sarcineaforme 

 is proved. A description of the organism is given. 



Tlie morpliologv of the fungus studied by the author does not agree 

 in all respects with the fungus described from Italy and Germany. Pro- 

 visionally the name Macrosporium sarcinaeforme is retained. 



The fungus enters the host usually between the epidermal cells of the 

 leaf and attacks at first the parenchyma, proceeding intercellularly. 

 Stomatal entrance was also observed. The cells are eventually killed 

 and invaded by the fungus, which finally sends up hyphae between the 

 epidermal cells (sometimes through stomata), on both sides of the leaf 

 and produces spores. Typical spots develop within 5 to 7 days. As a 

 result of infection the leaves eventually shrivel and fall to the ground. 



Inoculations have not been successful upon either the old stems or the 

 flower. The fungus readily attacks germinating seeds. 



Red clover is readily infected by the fungus. Inoculations made upon 

 local alsike clover has not been successful although Bain and Essary 

 claim to have seen it on alsike clover associated with badly diseased red 

 clover plants in Tennessee. 



Inoculation experiments have also been unsuccessful on other legumes. 

 The fungus on alfalfa called M. sarcinaeforme (U. S. D. A. Herb, 

 specimens) has been found to be a different form from the M. sarcinae- 

 forme on red clover from various parts of the United States. 



The fungus causes a disintegration and collapse of the cells of the 

 liost. After penetrating the epidermis, the fungus advances intercel- 

 lularly and intracellularly. 



The diseased spots do not transpire. The injury to the clover is 

 brought about by the unbalanced metabolism which leads to a depletion 

 of the cell reserves. 



