OTHER METHODS OF OBTAINING FOOD 209 
Rafflesiacee. 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 ig composed of St Y, 
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 
Rafflesia 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 
subaerial portions of 
GA®& 
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le. H, \ IN 
a. 101.—Piant or Melampyrum (Cow-Wutat) 
INFESTED WITH Cuscuta, 
14 
