EXERCISE XXI. 

 KINDS AND DISTRIBUTION OF CORN. 



Supplies for a Laboratory Section of Twelve. Six samples of each of the following : Flour corn ; dent corn ; 

 flint corn ; popcorn ; sweet corn. 



Part A. Kinds of Corn. 



1. Study carefully two or three ears of each kind of corn with which you are provided. 

 Record notes concerning each of the six different kinds of corn in the following order: 

 (In description of dent corn omit parts (b) and (f). 



(a) Common name, (b) Average size of ears relative to the average size of the sam- 

 ples of dent corn, (c) Average shape of ears — cylindrical or tapering, (d) State whether the 

 ears of the particular kind of corn under consideration are relatively slender or short and 

 thick, (e) Color of ears, (f) Size of kernels relative to the size of average kernels of dent 

 corn, (g) Shape of kernel. (See explanation of descriptive terms applied to corn.) (h) In- 

 dentation of kernels. (See explanation of descriptive terms applied to corn.) (i) Hardness 

 of kernels — soft, medium, hard, very hard. (May be determined by biting or cutting the ker- 

 nels.) 



2. Recall that in Exercise XIII Part B you made a careful drawing, of a typical section 

 of dent corn and named the more prominent parts. Examine, by way of review, this draw- 

 ing until you again have the gross structure of a kernel of dent corn well in mind. Make a 

 neat drawing natural size, of a longitudinal section of a representative kernel of each kind of 

 corn, excepting dent. This section is to be made parallel to the broader face of the kernel. 



.Sometimes the kernel may be split satisfactorily but usually it will be found necessary to 

 shave down from the back side of the kernel until the different kinds of starch present are ex- 

 posed to view. These drawings are not meant t,o show any great detail of the corn kernel 

 except the proportions of white and vitreous starch present. The contrast between these two 

 forms of starch may be brought out by shading the portion showing vitreous starch. Name 

 each drawing. 



3. Make a drawing, natural size, of the cross section of a representative kernel of each 

 kind of corn. This will give you a study of vitreous and white starch as seen in cross 

 section. Name each drawing. 



4. (a) What kind of corn is raised in largest quantities in the corn belt? (b) Where- 

 in does it have an advantage over pod corn? (c) Pop corn? (d) Flint corn? 



Part B. Distribution of Corn in the United States. 



5. On an outline map of the United States show in a general way the distribution of corn 

 by placing a dot in each state for every 1,000,000 bushels raised. (Note that the figures inthe 

 table below are given in thousands.) Distribute the dots evenly over Iowa, Illinois, Indi- 

 ana, Ohio, Missouri, Kentucky, Arkansas, Tennessee. In states bordering this group, namely, 

 Nebraska, Kansas, Oklahoma, Texas, Louisiana, Mississippi, Alabama, Georgia, South Caro- 

 lina, North Carolina, Virginia, West Virginia, Pennsylvania, Michigan, Wisconsin, Minnesota, 

 South Dakota, the dotting should be heaviest in that portion of the state nearest central Il- 

 linois and should gradually grow thinner as you move outward. States not mentioned in these 

 groups you will notice, have little effect upon the boundary of the corn belt. 



67 



