MISCELLAirmVS CROPS. 147 



group of which the " smnts " are important members. 

 Fig. 49 represents a transverse section of a root with 

 nodule. In very thin sections under high. power, the 

 nodules are seen to be filled with hyphse and spores. The 

 spores of this fungus are more or less v-shaped, and are 

 formed by division of the protoplasmic contents of the 

 hyphal filaments which ramify in the root-tissues of the 

 host-plant. Unlike most of the members of the Ustila- 

 ginece, the hyphge of Ustilago cucumeris i are not divided 



'Xyleni, 



Pfdoern 



Cortical 



PoJ'UlchjlTUL. 



Epidermis 



Fig. 49. — Tbansveese Section op a Boot with Nodule. 

 (Under low power.) 



by transverse septa. The hyphse (which are many times 

 :hicker than the cell- walls of the adjacent tissues) pass, 

 jeU by cell, through the cortex of the rootlet, and some- 

 imes across the intercellular spaces (Pig. 50). Branching 

 )f the hyphse is well marked in the tissues of the nodules, 

 md sometimes they send out lateral branches which end 

 ibraptly in the cells. The protoplasm of the nodular cells 

 ifter a time becomes vacuolated (Fig.' 50) and filled with 

 ipores. The spores of the cucumber-root fungus are 

 bund in the soils (where Cucwmis sativa has been grow- 

 ng) in the autumn and early winter, having been Hber- 



1 Originally described as Ustilago eucumis. 



