No. 403] 



THE PH. EN GAM US PARASITES 



21) 



which in the normal embryo would bear the plumule, is 

 not developed. If the descending end comes in contact 

 with no living root of another plant the whole embryo 

 dies, although the soil may be abundantly fertile. If it 

 reaches such a root it be- 

 comes attached to it and 

 develops a tuberous mass 

 at the place of contact. 

 From this mass spring out- 

 growths which penetrate the 

 bark of the root-host and 

 blend intimately with the 

 growing layer beneath it, 

 where they act as haustoria. 

 In this mass, also, by a kind 

 of blastemal germination, 

 buds, or substituent plant- 

 lets, are formed which pro- 

 duce the flowering stems. 

 Mo functional foliage and 

 no true roots are developed. 



vated crops; espe- 

 useuta they delay 



