MAMMOTH CLOVER RUST 



255 



ming's and in Gilson's solution, imbedded, cut, stained and the 

 peridial cells examined for morphological differences. The inner 

 walls are minutely verrucose like the other clover rusts, stride could 

 be found on the outer walls. The inner walls of the peridial cells 

 were so thin that difficulty was experienced in sectioning them. 



TaL.i06P0RE6 Oh M^A^A/OTH Cloi^E/^ 



Pig. 90. — IS^umbers 4 and 5 are germinating teliospores which have stood in 

 tap water for two weelts. In number 5 D=sporidlum germinating. 



Measurements of sections of the peridium showed the inner walls to 

 average 2 microns thick and the outer walls, 4 microns thick. The 

 inner walls of the peridial ce'lls of red clover rust are 3 microns; 

 outer, 6 microns. Of alsike, inner, 1 micron, outer, 3 microns. Thus 

 it would seem that the peridial cell thicknesses conform closer to 

 those of alsike clover than to red clover rust. The peridial cells are 

 shown in figure 86. 



