Grade. 

 Date. . 



EXERCISE 31 



THE COTTON PLANT 



Object. To study the structure of the cotton plant. 



Material. Cotton plants. 



Directions. 1. Root. (a) Examine the root. What kind of a root is it 

 according to Exercise 5? 



2. Stem. (a) Drawing No. 1. A node of the cotton plant showing a 

 fruiting and an undeveloped sterile branch. 



(6) Examine a short jointed plant. What is the average length of the 

 three lowest internodes? . _ inches. 



FIG. 41. A cotton boll and how it develops. A, the unopened boll; B, boll partly opened; C, boll 

 fully opened showing locks of fibre; D, the empty pod after the lock cotton has been gathered. (Produc- 

 tive Farm Crops.) 



Examine a long jointed plant. What is the average length of the three 

 lowest internodes? inches. 



3. Leaf. (a) Drawing No. 2. A leaf, showing shape of lobes and veins. 



4. Boll. (a) Drawing No. 3 (Fig. 41). A storm resistant boll and a 

 non-resistant boll. Label carefully showing the differences. 



(6) Label the locks in Drawing No. 3. 



5. Fiber. (a) Examine ripe and unripe fibers under the microscope. 

 Note the flattened twisted form of the ripe fibers. 



Drawing No. 4. Ripe and unripe fibers. Draw large. 

 (6) Examine bolls of a long and a short staple variety. 



