II.] 



PLANT STRUCTURE AND GROWTH. 



29 



Co.... 



lower end of the stem bear neither, and are called 

 roots. These latter serve a double purpose, they 

 fix the plant in the earth, and 

 also imbibe moisture from it. 

 They are never green, and they 

 avoid the light. The stem, on 

 the contrary, is ever seeking 

 the light, and usually green. 

 The leaf is a thin, flat plate 

 attached by a stalk to the 

 stem or branch. Fig. 36 re- 

 presents a thin slice cut through 

 the thickness of a leaf. Ep 

 shows the colourless epidermic 

 cells bounding the upper and 

 lower surfaces of the leaf. Be- 

 neath them is the green-celled 

 parenchyma, and between these 

 layers of parenchyma, which are 

 closely packed, there are others 

 loosely arranged (LP) to form 

 the intercellular spaces (IS). 

 Within this are seen the fibro-vascular bundles (Fv). 

 St marks the presence of the stomates. 



The food of a plant is of two kinds liquid and 

 gaseous. The liquid 

 food is obtained from 

 the soil through the 

 roots, and consists of v ~- i 

 water in which various 

 mineral salts are dis- 

 solved. These salts con- 



FIG. 35. 



st 



Sfc 



i.s... 



St Sb 



FIG. 36. 



