FRUITS 



255 



5. Why is decrease of moisture and increase of light desirable as the 

 fruiting season approaches? (126, 127; Exp. 90.) 



6. Why are turnips, carrots, and other fleshy roots unfit to eat if left 

 over till the plants have seeded ? (92, 287.) 



II. FLESHY FRUITS 



Material. — A specimen of each of the four principal kinds of fleshy 

 fruits. Examples of the pome are : apple, pear, quince, rose hip, haw ; of 

 the berry : grape, tomato, cranberry, currant, gooseberry, lemon ; of the 

 pepo : melon, squash, pumpkin ; of the drupe : peach, plum, cherry, dog- 

 wood. Specimens of the commoner kinds can nearly always be found in 

 the market ; if nothing better is available, pickled and dried ones may be 

 used — figs, prunes, dates, raisins, etc. 



— Examine with a lens 

 Can you make out the 



288. Dissection of a pome fruit. 



the outside of an apple or a pear, 

 lenticels ? What difference 

 in color do you notice be- 

 tween the ripe and unripe 

 fruit? What difference in 

 taste? What substance 

 would you judge from this, 

 do ripe fruits contain 

 which green ones do not? 

 Test both kinds for sugar 

 and starch ; which contains 

 the more of each? Strictly 

 speaking, sugar and starch 

 are merely different forms 

 of the same chemical compound. In ripe fruits the starch 

 has been cooked by the sun and converted into sugar. 



With the point of a pencil separate the little dry scales that 

 cover the depression in the center of the fruit at the end oppo- 

 site the stem. How many of them arc there ? How does this 

 accord with the plan of the flower as outlined in 229 ? They 

 are the remains of the sepals, as will be more apparent on 

 comparing them with the larger and more leaf like ones on 

 a hip, which is clearly only the end of the footstalk enlarged 



tj( . — Outside of an apple, show- 

 ing lenticels on the skin. 



