CLADOPHORA. 35 



LABORATORY WORK. 



GROSS STRUCTURE. 



1. With some plants in a dish of water compare with Ulothrix 

 as to color, coarseness, and position in the water. 



2. By lifting some plants from the water on a piece of white 

 paper, determine whether the diameter of a filament is 

 the same throughout. 



3. Examine the sides of a dish of plants which has been in 

 the laboratory a week or more to see if any of the germi- 

 nating spores are beginning to attach themselves to the 

 dish. 



MINUTE STRUCTURE. 



I. THE PLANT BODY. 



Mount one or two plants and under low power observe: 



1. The form. 



2. The relative size of segments * from base to tip. 



3. The form of segments at tips of branches as compared with 

 those lower down. 



4. The points at which branches arise. 



5. Sketch a small plant or part of a large one. 



II. THE SEGMENT. 



Under high power observe: 



1. The wall of a single segment of the plant enclosing: 



2. The protoplasm, of which (a) cytoplasm, (b) definitely 

 organized chloroplasts, and (c) a few pyrenoids may be 

 distinguished. 



1 In Cladophora each apparent cell is really a complex structure 

 within one cellulose wall. Such a segment is said to be a coenocyte. 

 To observe all the points suggested it will be necessary to have specially 

 stained specimens. 



