46 GLIMPSES INTO PLANT- LIFE 



of an ordinar}' plant ; because it is only by first 

 mastering all we can of one part of a plant, and 

 then comparing that part with other plants, that 

 we can hope to gain real knowledge. Accordingly 

 in our next chapter we shall take the root as our 

 starting-point, and ascertain its functions and uses, 

 and the part it has to play in the econom}- of the 

 plant. 



Specimens to be obtained : — Green stain on tree- 

 bark (^Protococcus) ; yeast ; annual, biennial, and 

 perennial plants ; water buttercup leaves ; vallis- 

 neria ; water-lily stems ; mare's-tail plant ; cacti ; 

 spurge ; orchids ; tillandsia ; plants growing in 

 wall crevices. 



