142 



soon form. The formation of these spores is very 

 much dependent on climatic influences, and in cold, dry 



FIG. 20. SECTION OF DISEASED TUBER, SHOWING MYCELIUM 

 TRAVERSING CELLS, AND ABSORBING CONTENTS. Marshall Ward. 



weather very few are formed. The mild, moist weather 

 of thundery seasons supplies the most favourable con- 



