100 OBJECT LESSONS IN BOTANY. 



LESSON XX.VI. 



LIFE OP THE .; ',ANT, OR ITS BIOGKAPHT. 



204. The water which the plant imbibes by its roots be- 

 comes sap in the stem, and circulates in every part as the 

 blood circulates in the' animal frame. The leaves, by their 

 broad, thin forms, serve as lungs, to bring all the sap which 

 passes through t^em into contact with the air and light. 



205. By this means the sap is changed into a^ nourishing 

 food, fitted to sustain the growth of the plant in every part. 

 Thus the leaves are designed, not only as an ornamental robe, 

 but as organs of breathing and digestion. 



206. In the second stage of growth, when the plant depends 

 no longer upon the seed for nourishment, it goes on increas- 

 ing in stature and multiplying its leaves and branches. It 

 now consists of thi-ee parts, namely, -roof, stem, and leaves. 

 These are called the organs of vegetation. 



207. The third stage of plant-life is the period of flowering. 

 Before this period, all its activity was devoted to its own 

 nourishment and growth. Now it begins to live and act for 

 the continuance of its own kind after it upon the e^rth, 

 according to the Divine decree in Genesis, i., 11. Some of 

 its buds undergo a striking change, and open each a flower 

 instead of a leafy branch. 



208. A flower is therefore a leafy branch transformed (as 



304. What becomes of the water ■which the roots imMbe ? ' What part do 

 the leaves act ? 



205. What change takes place in the sap ? 



206. What is the second stage of plant-life ? 



207. The third stage ? Whence come the flowers ? 



