78 LABORATORY MANUAL 



At the discretion of the instructor these may be shown 

 under the microscope. 



B. Venation. 



Examine the lilac leaf again. Note the continuation 

 of the petiole through the blade. This is called the 

 mid-rib, and its branches, the veins. Compare the 

 arrangement of the veins in the leaves of any lily with 

 that of the lilac leaf. How do they differ? These are 

 examples of the two kinds of venation. Make a draw- 

 ing of each and. label the lilac leaf, netted veined, and 

 the lily leaf, parallel veined. 



Exercise 48. Chloroplasts. 



Object: To study the organs which contain the 

 green coloring matter of plants. 



Apparatus 



Moss or Elodea leaves Scalpel 



Glass slides Compound microscope 



Cover glasses 



Directions: Place a drop of water on the center of 

 a glass slide. In this put a leaf of elodea or moss and 

 cover it with the thin glass cover. Examine this very 

 carefully under the low power of the microscope. Note 

 the oblong parts of which the leaf is composed. 

 Each of these parts is a cell. Examine one of 

 these carefully. What is its shape? What is the 

 appearance of the wall, cell wall, surrounding it? 

 Within the cell note the many small bodies, green in 

 color. What is their shape ? How many are there in a 



