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TEXTBOOK OP BOTANY 



Fig. 112. — A, dodder growing upon a 

 hop vine and bearing a cluster of flowers. 

 B, a cross section of the hop vine, showing 

 how the roots of the dodder grow into the 

 host until they reach its bast and wood. 

 After Kerner. 



suckers, which push into the tissues of the host. The 

 suckers grow until they reach the bast and wood of the host 

 plant. Then they are in a position to rob the host of its 

 manufactured food which is being transported in the bast, as 



well as of the water and 

 dissolved substances 

 that have come up 

 through the wood from 

 the roots of the host. 

 The primary root which 

 attached the dodder to 

 the soil now dies, as 

 does also the lower part 

 of the stem. The upper 

 part of the stem grows 

 rapidly, twining about 

 the host plant, branch- 

 ing, and producing many 

 suckers and great numbers of red flowers and fruits. But it 

 forms no leaves, has no chlorophyl, and is entirely dependent 

 upon the host for food. Some of the dodders are serious 

 enemies of the gardener and of the farmer because of their 

 attacks upon cultivated plants. 



The mistletoes differ from the dodders in the fact that they 

 have green leaves and so are only partly dependent upon the 

 host plant. The European mistletoe is well known because 

 its greenish branches, white berries, and evergreen leaves 

 are much used for holiday decorations. It lives high up 

 in the branches of trees, particularly of those trees which, 

 like the poplars, firs, and apples, have a thin, soft bark. 

 If a mistletoe seed germinates on a branch of such a tree, a 

 slender sucking branch root pushes into the tissue of the 

 host and grows until it reaches the wood. In the next year, 

 new branch roots grow which run upward and downward 

 within the bark of the host plant. From these branch roots 



