OAK. 183 



having thus noticed the prominent differences 

 between the two kinds, it is interesting to mark 

 what is common to both the particular character 

 of the venation and the beauty of the autumnal 

 colouring. The leaf is traversed by a prominent 

 and slightly-waved mid-vein from which waved 

 veins alternately diverge, on each side, at an acute 

 angle each branch vein proceeding to the apex 

 of a lobe. From these branches contorted veinlets 

 run irregularly, almost at right angles, and give 

 origin to a thick network of venules which, anas- 

 tomosing, cover the entire surface of the tissue 

 and provide the elaborate and beautiful system by 

 which life and vigour are carried into the spread- 

 ing foliage of the king of the woods. 



But as, on the wane of the year, the vital forces 

 of the tree become weakened, the full, deep green 

 hue loses its hold and the mellow tints of autumn 

 advance upon the leafy tissue. Plants may be 

 said to live by drinking and breathing. Their 

 roots, with the moisture which they extract 

 from the earth, absorb the chemical substances 

 which conduce to their life, health and beauty: 

 their leaves, through their almost countless stomata, 



