PARASITIC PLANTS 



343 



When the seed germinates it sends out a filament which pene- 

 trates into the soil and fixes the seedling firmly. The other end 

 grows upward, carrying up with it a httle swollen mass of food- 

 reserve, sufficient to support the growing seedling until it has had 

 some chance of reaching a suitable host. The upper end of the 

 seedling now sends out a filament which rapidly elongates, and, 

 growing upward, searches for some stem on which to climb. 



All this time the little mass of food-reserve is being rapidly 

 exhausted, and if the 

 young seedling fails to 

 reach a suitable plant 

 on which to climb it 

 soon dies, for its lower 

 extremity is unable to 

 absorb sufficient food 

 material from the soil ; 

 and the plant itself, 

 having no chlorophyll, 

 cannot decompose car- 

 bonic acid gas and build 

 up organic material to 

 add to its substance. 



Again, should the 

 young plant fail to reach 

 a favourable support, so 

 that it is of necessity 

 compelled to trail along 

 the ground, the filaments 

 which would soon pro- 

 duce suckers when 

 attached to a hving plant 

 have no power to form 



any structures capable of extracting food material from a damp 

 soil. 



Cu'cumstances being more favourable, however, the upper 

 filament eventually finds a stem, and immediately begins to twine 

 itself round it, making a few close coils in a clockwise direction. 

 Should the support prove to be a dead stem, little wartlike swell- 

 ings are produced at points where the two touch, and these serve as 

 a means of attachment for the cUmbing filament, but 'no suckers 

 are formed. If, however, the filament surrounds a living stem, each 



The cloveh Dodder, with a Separate Cluster 

 OP Flowers representing the Natural 



SIZE. 



