212 STUDY OF COMMOK PLAKTS. 



With the fruits of the sugar maple, compare those of 

 the red and silver maples, noting all the external and 

 structural differences by which they may be distinguished. 



Licaves. 



Compare the leaves of all three kinds until you are able 

 to distinguish the species at sight by means of the leaves 

 alone. 



Finally review the observations made thus far, see if 

 anything is to be added, and write a complete account 

 of the characters common to all three species and also of 

 those peculiar to each. 



SPECIAL STUDIES. 



I. Critical comparison of the Box-elder, Negwndo 

 aceroides, Moench., with the maples. Does it 

 have the essential characters of a maple ? 



II. Origin of polygamous flowers. Some light may be 

 thrown on this by a comparison of as many flow- 

 ers as possible of the red maple and other species 

 of maple. 



III. Evidences of relationship of the maple and buck- 



eye or horse-chestnut. 



IV. Habits of different species of maple in regard to 



germination. 



