OTHEK METHODS OF OBTAINING FOOD 209 



Rafflesiacece. The em- 

 bryo, after emerging 

 from the seed, pene- 

 trates the cortex of its 

 host, usually a root, 

 though not always, and 

 gradually forms a hol- 

 low cylinder surround- 

 ing its woody centre. 

 This sheathing struc- 

 ture is composed of 

 rows of cells, and in 

 appearance resembles 

 the mycelium of a fun- 

 gus. Buds arise upon 

 this investment, which 

 eventually burst the 

 cortex above them, and 

 protrude through the 

 host plant. These, in 

 Rajflesia itself, develop 

 a single flower which, 

 in some cases, is of 

 enormous size. The 

 plant produces no out- 

 growths of any kind ex- 

 cept the buds described. 

 Other genera show some 

 modification of this 

 structure, but exhibit 

 exactly similar physio- 

 logical peculiarities. 



Certain other para- 

 sites which resemble 

 these in many respects 

 differ in attacking only 



FIG. 101. PLANT OF Mdampyrum (COW-WHEAT) 



INFESTED WITH CuSCUta. 



14 



