A LESSON ON BUTTERCUPS. 207 



GENERAL FACTS BEGARDING FUNCTION. 



The Root. 



We omit all details of structure at present. What are 

 its functions ? 



(a) It holds the plant in the soil. Obviously fixation is 

 an important function of the root. Notwithstanding the 

 fact that there are plants endowed with powers of loco- 

 motion, and animals that are fixed and sedentary, we come 

 at the outset to one of the biggest contrasts in mode of 

 life, in method of reacting to environment, between animals 

 and plants. Plants are in general habits stationary 

 organisms. 



(6) Secondly, the root is absorptive. It absorbs mineral 

 ingredients dissolved in water from the soil. This is also 

 an important fact distinctive of plant life. 



These are the chief uses of roots, but we may mention 

 one other which although a subsidiary one is of common 

 occurrence in some other plants, but is not noticeably so 

 here. 



(c) Some roots are utilised for the storage of reserve 

 food products. 



The Stem. 



(a) Plants have direct relations with the sun, and the 

 first function of a stem undoubtedly is to hold up the parts 

 of it which deal in sunlight, viz. the leaves. They also 

 need air (carbon dioxide), and here again the stem, by 

 means of its length and its branching, spreads out to the 

 atmosphere the leaves which are more especially reacting 

 to it. And the flowers must not be forgotten, which in 

 most cases must for fulfilment of their functions be 

 exposed to insects, to wind, or to other fertilising agents. 



But here also some secondary functions may be noted. 



