150 THE GREENWOOD TREE. 



seedlings with a little water, containing in solution 

 small quantities of manure-stuffs, and the plants will 

 grow as well as on their native heath, or even better. 

 Indeed, nature has tried the same experiment on a larger 

 scale in many cases, as with the cliff-side plants that 

 root themselves in the naked clefts of granite rocks ; the 

 tropical orchids that fasten lightly on the hark of huge 

 forest trees ; and the mosses that spread even over the 

 bare face of hard brick walls, with scarcely a chink or 

 cranny in which to fasten their minute rootlets. The 

 insect-eating plants are also interesting examples in their 

 way of the curious means which nature takes for keeping 

 up the manure supply under trying circumstances. 

 These uncanny things are all denizens of loose, peaty 

 soil, where they can root themselves sufficiently for 

 purposes of foothold and drink, but where the water 

 rapidly washes away all animal matter. Under such 

 conditions the cunning sundews and the ruthless pitcher- 

 plants set deceptive honey traps for unsuspecting insects, 

 which they catch and kill, absorbing and using up the 

 protoplasmic contents of their bodies, by way of manure, 

 to supply their quota of nitrogenous material. 



It is the literal fact, then, that plants really eat and 

 live off carbon, just as truly as sheep eat grass or lions 

 eat antelopes ; and that the green leaves are the mouths 

 and stomachs with which they eat and digest it. From 

 this it naturally results that the growth and spread of 

 the leaves must largely depend upon the supply of 

 carbon, as the growth and fatness of sheep depends upon 

 the supply of pasturage. Under most circumstances, to 

 be sure, there is carbon enough and to spare lying about 



