EXERCISE 41 



A STUDY OF THE WHEAT PLANT 



Statement. The plant consists of roots, stems, leaves, flowers, and fruit. The relationship of the 

 parts and the difference in the time at which they appear are strikingly shown in the case of the 

 wheat plant. 



Object. To study the structure and relationship of the principal parts of a wheat plant. 



Materials. Wheat seedlings grown in the classroom and a bundle of full-grown plants. 



Directions, i. Study the arrangement and structure of the roots, stems, and leaves of the wheat 

 seedlings and of the mature plants. Make a diagram showing the position and relation of the parts. 



Compare the wheat seedlings and a full-grown 

 plant to determine what changes have occurred, 

 and what new structures have appeared. Examine 

 the relationship of the grain formed to the husks 

 surrounding it. Explain how the kernel is pro- 

 tected. Determine how the flower is pollinated. 



2. Ascertain, by counting, the average number 

 of plants on a square foot in a near-by wheat field, 

 (i) in the fall, shortly after germination, and (2) in 

 the spring when the plants are starting their growth 

 again. Explain the cause for the difference shown. 

 Count the number of shoots coming from different 

 plants and compute the maximum and minimum 

 number produced by a plant. Note any evidence 

 of winter killing and explain the cause. Is the 

 damage uniform throughout the field? If not, ex- 

 plain why. (3) Visit the wheat field as late in the 

 season as possible before school closes and note the 

 thickness of the stand and the size of the heads on 

 the different shoots of a plant. Compare the size 

 and type of the heads of different plants. Note the 

 difference in the rankness of growth, color of foliage, 

 and thickness of stand between different spots in 

 the field. Explain the reason for any difference that 

 may exist. Give the cause for any lodging that 

 may have occurred. Draw graphs on the opposite 

 page, showing results of your observations. 



Questions. How does one wheat seed produce a 

 number of plants ? How does the habit of stooling 



Fig. 50. A young wheat plant showing the beginning of an 

 elaborate system of roots, stalks, leaves, and heads 



affect the crop of wheat? Why is spring wheat seeded thicker than winter wheat? Why is the former 

 seeded thicker in the late sown than early sown wheat? Are the pollen and ovules of the wheat present 

 in the same flower? How does the wheat plant differ from the corn plant in this respect? Is wheat 

 self fertilized or cross fertilized ? Explain the difference between the two. 



References. Waters, H. J. Essentials of Agriculture, pp. 156-158. Ginn and Company. Carleton, 

 M. A. The Small Grains, pp. 27-32. The Macmillan Company. Dondlinger, P. T. The Book of Wheat, 

 pp. 1 1-29. Orange Judd Company. 



[82] 



