56 LABORATORY PRACTICE CHAP. X 



3. Make a sketch to show this. 



4. Do these spines represent stem-, leaf-, or root-structures ? 



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



III. Examine a branch of the Locust Tree or of the 

 Spiny Acacia and notice : 



1. The pairs of spines and 



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



the leaves are not present). 



3. Make a sketch to illustrate this. 



4. Do these spines represent stem-, leaf-, or root-structures? 



5. Can you state even more exactly just what particular 



structures they represent? 



6. Write down your answers, and the reasons for them. 



IV. Examine branches of the Rose or of Brambles (Black- 

 berry, Raspberry, Thimbleberry, etc.) and notice : 



1. The prickles, and 



2. Their relations to the leaves (or leaf-scars). 



3. Make a sketch to represent this. 



4. Cut one into two halves longitudinally, and make a 



sketch. 



5. Do these prickles represent stem-, leaf-, or root- 



structures ? 



6. Write down your answer, and give your reasons for it. 



V. Examine a leaf of the Thistle and notice : 



1. The numerous sharp spines upon each leaf. 



2. Make a sketch of this leaf. 



3. What other leaves can you think of, that are protected 



in the same way? Write down the list. 



VI. Examine the leaves and stems of some Buttercups, 

 Wormwood, Mayweed, or Eschscholtzia, and notice : 



