212 THE EVOLUTIONIST AT LARGE. 



all other plants, and is able to spread itself 

 boldly to the light on every side. It has 

 abundance of sunshine as a motive-power of 

 growth, and abundance of air from which to 

 :xtract the carbon that it needs. Hence it 

 and all its ancestors have spread their leaves 

 equally on every side, and formed large flat 

 undivided blades. Leaves such as these are 

 common enough ; but nobody thinks of call- 

 ing them pretty. Their want of minute sub- 

 division, their monotonous outline, their dull 

 surface, all make them ugly in our eyes, just 

 as the flatness of the Cornish plain makes it 

 also ugly to us. Where symmetry is slightly 

 marked and variety wanting, as in the cab- 

 bage leaf, the mullein, and the burdock, we 

 see little or nothing to admire. On the other 

 hand, ferns generally grow in hedge-rows or 

 thickets, where sunlight is much interrupted 

 by other plants, and where air is scanty, most 

 of its carbon being extracted by neighbouring 

 plants which leave but little for one another's 

 needs. Hence you may notice that most 



