A MANUAL OF BOTANY 13 



Draw examples of fibrous roots. 



Soils and form. Examine the roots of plants that have 

 grown, some in dry sand or clay and others in moist ground, 

 others again that have grown in ordinary soil conditions. 

 What influence, if any,. do you find the soil conditions to 

 have upon the root form ? Why do storage roots have 

 such an excessive amount of reserve food? Seek to 

 discover if this excessive storage is found in cultivated 

 plants, or is found in wild ones also. What effect might a 

 soil very rich in })lant food have upon the form of a tap root ? 



Other root forms. Examine the aerial roots of poison ivy, 

 English ivy, or other similar climbers. What purpose have 

 these roots ? 



If possible, look at some large fig or pandanus trees in 

 the greenhouses of the pjublic parks, and observe the air 

 prop roots. Look at pictures of banyans and other tropical 

 trees, and observe the same features. Examine also, if 

 obtainable, the lower end of a cornstalk iov projj roots. 



In the orchid house, examine, or in books on orchids, read 

 about their air roots and their use. 



What differences woidd you find between the roots of 

 annuals and those of biennial and perennial plants ? 



Show all such roots by diagrams or drawings. 



3. Root and Seed Composition Experiments^ 



Statement. These experiments may be made by the stu- 

 dent, but in many cases it will be desirable to have them 

 demonstrated by the instructor, the student taking full notes 

 of apparatus and results. 



Tests. Various composition tests are : — 



1. The starch test which has been given ; 



2. The grape sugar test (given in Exp. in Seedlings) ; 



3. The albumen test (proteids). 



1 Have been referred to under the seed study. 



