214 THE TEACHING BOTANIST 



forms a growth system) and that one, two, or three run out 

 through the petiole and branch profusely, ending either as very 

 small veinlets anastomosing, or else each ending abruptly in a 

 small green area (shows well in Asarum) ; the tapering of the 

 veins regularly and for mechanical reasons. With eosin or 

 safranin prepare tumblers filled with red dye and place cut 

 shoots in them ; in a few minutes the fibro-vascular system will 

 be completely stained. Slides and covers should be given to 

 allow students to mount all sections in water. Excellent thin 

 sections can be made with their scalpels, which they may 

 sharpen on the laboratory whetstone provided for the purpose. 

 A diagram like that called for in Exercise 38 is shown in 

 Fig. 20, where the colors are represented by special shading. 



XI. The Cellular Anatomy of the Shoot the 



Leaf in Particular 



In studying cellular anatomy, one is dealing directly 

 with cells. 



39. What is the structure of a typical plant cell ? 

 Answer by a study of the living cell in the 



stamen-hair of Tradescantia. For this the 

 compound microscope is needed, the use of 

 which will be explained to you. 



40. What is the cellular structure of the protective 



system of a typical leaf ? 



Answer by a study of the epidermis of Trades- 

 cantia, which may be peeled off after a study 

 of it in position. 



Notice particularly the guard cells and stomata. 



