ROOT CROPS. 



491 



Fig. 3.- Diagrammatic representation o! a square cut from a potato leat infected with 

 Phytophlhora inftstans. 



The branching eonidiophores are shown emerging through the stomata (breathing 

 pores) on the under-s UI face of the leaf, and bearing many spores. 

 The other structures shown are two kinds of plant hairs (a) Long-pointed hairs, 

 and (6) Short hairs with knob ends. 



(Redrawn after Bureau of Plant Industry Bui. 215.) 



