14 HORTICULTURE FOR SCHOOLS 



EXERCISES 



EXEECISE I. Wild and domesticated forms. 



Materials. Mature specimens of the following plants showing 

 roots, stems, leaves, flowers, and fruit: Tomato, potato, nightshade. 



Procedure. Note the general appearance of these different plants. 

 Does a superficial examination reveal any similarities? Compare 

 closely the leaf of the potato with that of the tomato and the night- 

 shade. Point out all the similarities and all the differences that you 

 can detect. Do the same with the flowers of the three plants, examining 

 the structure of the flowers in some detail. Count the sepals, petals, 

 and stamens of each. Note the form of the corolla in each case. Does 

 this suggest any relationship existing between the different plants? 



It may be difficult to find a potato fruit, but if possible secure one 

 and compare it with the fruit of the tomato and of the nightshade. 

 What evidence is there here of similarity of structure? Why is it that 

 the potato is grown for its tubers while the tomato is grown for its 

 fruit? The structure shows that they have a close botanical relationship. 

 The potato and tomato are indigenous to the Americas, while some 

 form of the nightshade is found in widely separated parts of the world. 

 A study of the history of the tomato shows that a hundred years ago 

 it was regarded as poisonous and this prejudice against it disappeared 

 only recently. The present cultivated forms are also a very recent 

 development. 



Do you think it would be possible to make such improvements in 

 the nightshade as have been brought about in the tomato? Explain 

 fully the reasons which lead you to your conclusion. 



Why does the potato not bear fruit as does the tomato? Do you 

 think it would ever be possible to secure a potato which would bear 

 fruit regularly? If so, how could this be accomplished? Would there 

 be any advantage in having such a potato? 



EXERCISE II. 



Materials. Wild forms native to the student's locality. 



Procedure. Bring to class samples, including, if possible, fruit of 

 any plants growing wild in your locality which are closely related to 

 cultivated forms. For example: In many parts of the United States 

 there can be found wild cherries, plums, grapes, strawberries, crab- 

 apples, or other plants. Are these specimens which you have brought 

 truly wild or are they feral? Explain the difference between the two 

 terms. Are these specimens superior in any way to the cultivated 

 forms? (In answering this question think of their resistance to disease, 



