THE STEM. 43 



6. The pith comes last, and presents no difficulties. 



7. Having compared the two sections throughout, go 



over them again and see if all is clearly under- 

 stood. Make yourself familiar with all the details 

 of structure. Note what cells contain chlorophyll, 

 where starch occurs, the action of Schulze's solu- 

 tion on different parts, whether the sieve-tubes 

 show any peculiarities corresponding to their name, 

 how the cork originates, the manifest resistance of 

 the cork cells to reagents, and so on. Write a full 

 account, and introduce drawings wherever they are 

 required to make the description clear. 



8. Finally cut tangential longitudinal sections, and 



compare with the preceding. 



III. Stem of Indian corn. Cut thin transverse sections. 

 Examine first with the low and afterwards with the high 

 power. The following parts are seen : 



1. The epidermis and sub-epidermal tissue, forming a 



continuous peripheral zone of thick-walled cells. 



2. Fibro-vascular bundles,^ more numerous near the out- 



side of the stem. 



3. Fundamental tissue, consisting of large cells similar to 



those composing the pith of the apple-tree stem. 



IV. To understand these parts it will be necessary to 

 compare them carefully with the same structures as seen 

 in longitudinal section. Accordingly, with both trans- 

 verse and longitudinal sections on the slide, study each 

 part in detail. 



1. Observe the epidermis from both points of view. 



Draw a few cells. 



2. The fibro-vascular bundles present a somewhat com- 



plicated structure. They are bounded externally 

 1 Or simply vascular bundles, perhaps a preferable usage. 



