530 Home Nature-Study Course, 



LESSON VL 



THE CORN PLANT. 



Purpose. — To lead the pupil to give careful attention to the structure 

 of this plant. 



The material necessary is simply a mature corn stalk which may be 

 studied in the field, or pulled up by the roots and studied in the school- 

 house. 



Ohserz'ations for pupils: 



1. Describe the central stem. 



2. How many joints or nodes are there in it? 



3. Of what use to the plant are these nodes ? 



4. Are the joints or nodes nearer each other at the bottom or top 

 of the plant ? 



5. Where do the leaves come off the stem and how far do they clasp 

 it at their bases ? 



6. Of what use is this to the plant? 



7. See the little growth on the leaf where it leaves the stalk, which 

 prevents the rain from flowing down between the stalk and the clasping 

 leaf; of \\hat use is this? 



8. What is the structure of the leaf and the direction of the veins 

 or ribs? 



9. How does this structure aid the plant? 



10. Are the edges of the corn leaf straight or ruffled? 



11. Of what use is this ruffled edge? 



12. Describe the two kinds of roots on the corn plant and explain 

 the use of each? 



Facts for the teacher. — In studying the maize it is well to keep in mind that a 

 heavy wind is its worst enemy; such a wind will lay it 'low and from such an 

 injury it is difficult for the corn to recover and perfect its seed. Thus the mechan- 

 ism of the corn stalk and leaf is for prevention of this disaster. The corn stalk is 

 practically a strong cylinder with a pith}- center; the fibers of the stalk are very 

 strong and at short intervals the stalk is strengthened by the hard nodes and joints ; 

 if the whole stalk were as hard as the nodes it would be inelastic and break instead 

 of bend ; as it is the stalk is very elastic and will bend far over before it breaks. 

 The nodes are nearer each other at the bottom, thus giving strength to the base; 

 they are farther apart at the top where the wind strikes and where bending and 

 bowing of the stalk is necessary. The leaf comes off at a node and clasps the stalk 

 for a considerable distance, thus making it stronger, especially toward the base. 

 Just where the leaf starts away from the stem is a little growth called the rain- 

 guard ; if water should get between the stalk and the clasping leaf it would aff"ord 

 harbor for destructive fungi. The structure of the corn leaf is especially adapted 

 to escape injury from the wind; the strong veins are parallel with a strong but 

 flexible midrib at the center; often after the wind has whipped the leaves severely 

 only the tips are split and injured. The edges of the corn leaf are ruffled and 

 there is a wide fold in the edge at either side where the leaf leaves the stalk ; this 



