52 
Garden Work 
into the branches and leaves, which in the meantime have 
been formed. There it is manufactured into food sub- 
stances for its own nutrition and growth. Unless grown 
in large quantities on a tree it does very little damage to 
the host plant, as it only takes the food material from a 
small part of the tree, while the rest of the layer all round 
is sending up the full quantity. Such plants are known 
as partial parasites; partial, because, though living on 
another tree, and taking some of the nourishment from it, 
Tentacles on Leaf of Sundew 
yet they have green leaves which absorb the carbon di- 
oxide from the atmosphere, and so manufacture their own 
food for the leaves. These partial parasites can be intro- 
duced into a tree by procuring ripe berries, which are 
placed into a slit made in the bark of the tree. 
The Cuscuta or Dodder is another peculiar plant. Its 
seeds germinate in the ground, sending up a filamentous 
stem which twines itself round certain plants, and at 
various points sends out sucker-like processes which pene- 
trate the tissues of its host plant, making their way right 
into the wood fibres and drawing from them the food 
which has been manufactured in the green leaves of the 
