122 



THE SECOND BOOK OF BOTANY. 



You see that flowers present symmetry of arrange- 

 ment as well as symmetry of numbers, and it is im- 

 portant that you should observe them in this respect. 

 Determine what parts of the flower you are studying 

 alternate symmetrically, and where the symmetry 

 fails. You will often find these observations valua- 

 ble in classification. 



EXERCISE XLIII. 

 "Leaf Arrangement. Phyllotaxis. 



FIG. 268. 



