OTHER METHODS OF OBTAINING FOOD 203 
which eventually burst 
the cortex above them, 
and protrude through 
the host plant. These, 
in Rafilesia itself, de- 
velop a single flower 
which, in some cases, 
is of enormous size. 
The plant produces no 
outgrowths of any 
kind except 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 sub-aerial por- 
tions of their hosts. 
The most easily ob- 
served of these is the 
Dodder (Cuscuta), 
which often attacks 
the cow-wheat or the 
clover (fig. 101). The 
seed when germinat- 
ing puts out an em- 
bryo which bears. no 
cotyledons. Germina- 
tion takes place on the 
ground, and the em- 
bryo grows to a length 
of about an inch, Its 
» 7! 
‘A 
“Sa J 
ans 
=e 
aN 
ahi, 
SES, 
Ea 
A, 
= 
a 
o ii AN 
) fy \ \ 
a y WW 
Ee 
‘Fic. 101.—Priant or Melampyrum (Cow- 
WHUBAT) INFESTED WITH Cuscuta, 
