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wash the sections into a watch-glass, place some 

 of those made through the internode upon a slide 

 with a drop of water, put on the cover-glass, and 

 examine with the low power. Note that the sec- 

 tion consists of a central or internodal cell sur- 

 rounded by the cortical cells. How does the 

 internodal compare with the cortical cells in size i 

 In shape ? In contents ? Is the central cell di- 

 vided? Does it communicate with the cortical 

 cells ? Does it extend through the nodes, or is 

 there a single internodal cell for each internode ? 

 How many cortical cells are there ? Do they have 

 the usual contents of the cells of green plants, i. e., 

 protoplasm or primordial utricle, vacuole, starch 

 grains, chlorophyll bodies, etc. ? Note the nodal 

 cells and compare them with the others. Com- 

 pare several specimens to see if you can find any 

 variations regarding the topics just studied. 

 Make drawings illustrating your results. 



h. The leaves. — With, the sealpel cut loose from the 

 stem two or three vigorous leaves, mount them in 

 a drop of water, and examine under the low power. 

 What is the shape of the leaf ? Does it, like the 

 main stem, consist of segments ? If so, how many 

 segments do you find in each leaf? Examine 

 several leaves to see if the number is constant. 

 Do you find nodal, internodal, and cortical cells ? 

 Are the latter arranged in spirals? Do these 

 cortical cells differ in any important particular, 

 as shape, arrangement, contents, etc., from those 

 on the stem? Are cortical cells present on all of. 

 the internodes of the leaf? If not, which inter- 

 nodes lack them ? Are these uncorticated inter- 



