64 TERRESTRIAL ADAPTATIONS. 



subsist through a year, where the mean tempera- 

 ture was only 50, where the temperature of the 

 summer quarter was only 64, and where the 

 mean temperature of a whole quarter of the year 

 was a very few degrees removed from that at 

 which water becomes solid. He would suppose 

 that scarcely any tree, shrub, or flower could 

 exist in such a state of things, and so far as the 

 plants of his own country are concerned he would 

 judge rightly. 



But the countries further removed from the 

 equator are not left thus unprovided. Instead of 

 being scantily occupied by such of the tropical 

 plants as could support a stunted and precarious 

 life in ungenial climes, they are abundantly 

 stocked with a multitude of vegetables which 

 appear to be constructed expressly for them, in- 

 asmuch as these species can no more flourish at 

 the equator than the equatorial species can in 

 these temperate regions. And such new supplies 

 thus adapted to new conditions, recur perpetually 

 as we advance towards the apparently frozen and 

 untenantable regions in the neighbourhood of the 

 pole. Every zone has its peculiar vegetables ; 

 and while we miss some, we find others make 

 their appearance, as if to replace those which 

 are absent. 



If we look at the indigenous plants of Asia and 

 Europe, we find such a succession as we have 

 here spoken of. At the equator we find the 



