PROTECTION 55 



CHAPTER X 



PROTECTION 



THE plant finds itself exposed to numerous enemies, and 

 many peculiarities of habit and structure assist directly in 

 protecting the plant against them. For the present we need 

 consider only the ways in which the plants protect them- 

 selves against the attacks of those animals which eat its 

 substance, either grazing animals, or insects and their larvae, 

 such as caterpillars and the like. We are to notice not only 

 the particular means employed, but also which of the three 

 primitive organs (i.e. root, stem, or leaf) of the plants is 

 modified, in each case, to provide the means. 



I. Examine a branch of the Orange or Thorn and 



notice : 



1. The stout thorns, and 



2. The relation of each to the adjacent leaf (or leaf-scar if 



the leaves are not present). 



3. Make a sketch of a portion of the branch with one thorn 



and its adjacent leaf. 



4. Bo these thorns represent stem-, leaf-, or root-structures? 



5. Write down your answer and the reasons for it. 



II. Examine a branch of the Barberry, the Gooseberry, 

 or the Currant, and notice : 



1. The weak spines, and 



2. The relation of each to the adjacent leaf or bud. 



