THE MAPLE FAMILY. 211 



III. Next take specimens that have well-developed 

 pistils. 



1. Are stamens present? If so, how do they compare 



with those of the flowers previously studied ? 



2. Are the floral envelopes alike in all the flowers ? 



3. Notice the form and structure of the pistil. How 



many carpels are there? How many ovules in 

 each cell? 



IV. Compare with these the flowers of the silver maple, 

 noting carefully all the points of likeness and difference. 



1. Are petals present? 



2. Do all the flowers have both stamens and pistils? 



3. Is the ovary smooth or hairy ? 



4. Does it agree in structure with that of the red 



maple ? 



5. Do different specimens exhibit any variation as to 



the number of carpels ? 



V. Compare flowers of the sugar maple, which open 

 some days later, with those of the red and silver maples. 



1. Are there any differences as regards 



a. Form and position of the flower clusters ? 



h. Color of the calyx? 



c. Structure of the essential organs ? 



2. Are all the flowers of the same tree alike ? How is 



it with those of the red and silver maples in this 

 respect? _ 

 The maples are described as being " polygamo-dioe- 

 cious." What is meant by this ? Do you find that 

 the facts correspond with the statement? 

 Fruits. 



Study next fruits, taking first those of the sugar maple 

 gathered the preceding fall. 



