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tacle? "With a scalpel cut open the swollen end 

 of a branch. What is the appearance of the 

 inside ? 



Sketch a plant and show all of the features ob- 

 served. Examine the tips of branches which are 

 not swollen. Do they likewise bear conceptacles ? 

 Note that the extreme tip is indented. In the bot- 

 tom of the depression lies the growing point. 

 Put a piece of the thallus into fresh water. Does 

 the piece gradually become slimy? Does it in- 

 crease or decrease in size? Does it go through 

 these changes in salt water? "Why must speci- 

 mens be studied in salt water, or in alcohol, or in 

 glycerine and alcohol ? 



Microscopic Examination. 



a. The branch. — Hold a piece of a young branch of 

 a preserved specimen between two pieces of pith, 

 and with the razor cut both transverse and longi- 

 tudinal sections, and examine in glycerine with 

 the low power. "What is the shape of the outline 

 of the branch ? Notice the arrangement of cells 

 in the section, certain cells forming a surface or 

 cortical band, which shades oflp through a layer 

 of parenchyma into a central mass or me- 

 dulla. Do the former resemble the cortical cells 

 of Chara in arrangement, shape, size, color, etc. ? 

 Is the position of the midrib well defined ? Put 

 on the high power and examine the same section. 

 Study the cortical cells. How are they arranged ? 

 How far towards the middle of the branch do they 

 extend? Are they sharply marked ofiP from the 

 underlying tissue ? "What is their color ? Do you 

 find the same color elsewhere in the section ? 

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