THE STUDY OF THE DANDELION. 21 



and thus regulating the escape of moisture in dry or 

 wet weather. 



It can be shown that the leaves breathe or respire for 

 the plant in a way corresponding to our lungs, and 

 that they also take in gaseous food from the air, and 

 convert this and part of the water absorbed by the root- 

 lets into starch and other plant foods. For the latter 

 process they need the help of the sun. For this work 

 they are adapted by their position and arrangement, 

 exposing them to the sun, and by their form, with great 

 extent of surface, through which the gases can pass, 

 and on which the sunlight can act. Their effort to 

 change position by bending away from the shade and 

 toward the light, and their greater length in high grass 

 or shaded places, aid them in getting help from the sun. 

 The strong veins, with branches on each side, extending 

 into the tip of each division or lobe, aid in lifting and 

 supporting every part of each leaf in the sunlight, as 

 well as in directing water to the roots, and in carrying 

 water and dissolved food into every part of the leaf. 



Now, the form and structure of the dandelion leaf 

 mean something. We begin to see a reason for the 

 structure in the adaptation to surroundings or environ- 

 ment. 



The leaves of the dandelion are adapted by their posi- 

 tion, arrangement, form, venation, and movements: 



First. To direct water to the roots. 



Second. To protect buds at their base. 



Third. To throw out water, with the aid of the sun. 



Fourth. To breathe. 



