516 



THE UNIVERSE. 



which is unlimited, and many of which, born amid the 

 debris of former cataclysms, still vegetate full of sap and 

 vigor. 



De Candolle, who puts forward this opinion, admitting 

 the hypothesis of Gaudichaud, considers the giants of our 



215. Dragon' s-Blood Tree of the Island of Teneriffe : Diwcena Draco (Linnaeus). 



forests as so many aggregates of individuals, or buds, an- 

 nually succeeding on the stem, which thus represents a liv- 

 ing soil. This stem grows on century after century, and 

 only succumbs by accident, as when struck by lightning, 

 or when its suckers cannot find nutritive juices. 



