CHAPTER VII 

 STRUCTURE OF THE STEM 



STEM OF MONOCOTYLEDONOUS PLANTS 



81. Gross Structure. — Refer back to the sketches of the corn- 

 seedling to recall something of the early history of the corn-stem. 

 Study the external appearance of a piece of corn-stem or bamboo 

 two feet or more in length. 

 Note the character of the outer 

 surface. Sketch the whole piece 

 and label the enlarged nodes 

 and the nearly cylindrical inter- 

 nodes. Cut across a corn-stem 

 and examine the cut surface 

 with the magnifying glass. 

 Make some sections as thin as 

 they can be cut and examine 

 with the magnifying glass 

 (holding them up to the light) 

 or with a dissecting microscope. 

 Note the firm rind composed of 

 the epidermis and underlying 

 tissue, the large mass of pith 

 composing the main bulk of 

 the stem, and the many little 

 harder and more opaque spots, 

 which are the cut-off ends of 

 the woody threads known as fihro-vascular bundles (Fig. 38, cv). 



Split a portion of the stem lengthwise into thin translucent slices 

 and notice whether the bundles seem to run straight up and down 



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Fig. 38. Diagrammatic Cross-Section 

 of Stem of Indian Com. 



CO, fibro-vascular bundles; gc, pithy 

 material between bundles. 



