FRUITS. 89 



II. Make a transverse section and examine the internal 

 structure. Ascertain 



1. Where the seeds are attached. 



2. Number and position of the placentae. 



3. Number of carpels. 



SUGAR MAPLE. Acer saccharinum, Wang. 



I. Taking dried specimens, gathered the preceding fall, 

 notice 



1. The form of the wings. 



o 



2. Their size as compared with the rest of the fruit. 



3. The lightness and strength of the whole structure. 



What do you infer as to the mode of dissemi- 

 nation ? 



II. Make an outline sketch of one of the two halves, 

 mericarps, into which the fruit separates. 



III. Soak some of the fruits in water, and after an 

 hour notice what changes have taken place. With a 

 sharp knife or scalpel remove the pericarp. How does its 

 outer part differ from the inner in texture? Has the seed 

 become wet? Describe the means of protection of the 

 embryo. 



IV. Taking a mericarp that has soaked a longer time, 

 or better, one that has lain on the moist ground from 

 the time of its fall, remove the pericarp so as to expose 

 the seed in its natural position. Next remove carefully the 

 seed-coats and examine the embryo. Observe the way it 

 is folded together and the form of the radicle and coty- 

 ledons. 



V. Classify the fruit. 1 



1 Cf. Goebel, Outlines of Classification and Special Morphology, p. 

 428 ; Gray, Structural Botany, Chap. VII. 



