204 



LETTERS OlS TREES. 



points both of resemblance and contrast between them 

 and the grasses. Slender and short-lived like them, 

 annuals in fact as they are, they reproduce themselves 

 also both by seeds and buds. And, as in the case of 

 the grasses, the seeds of tree-plants serve to diffuse 

 their species over the surface of the ground, while 

 the buds cause sets of them to cluster together. 

 Grass-plants and tree-plants differ only in this, that 

 the former cluster together sideways, each plant strik- 

 ing down directly into the soil, and so they come 

 to cover the ground as with a carpet, while tree- 

 plants cluster together in the vertical direction, and 

 parasitically one set above another, and so they come 

 at length to form masses which rise upwards — columns 

 which point to the heavens above. 



23. Compare them next with the cereals, and con- 

 sider the mutual relations of both to man. Created 

 as expressly for man's use as the cereals have been, 

 and remotely as essential to his existence as these are, 

 tree-plants have yet been differently constituted in 

 respect of the conditions of their existence. The 

 cereals, as we have seen, cannot exist without man's 

 toil and care. Tree-plants can and do exist indepen- 

 dently of this. It might have been otherwise ordered, 

 however. They might (hke the cereals) have been 

 made dependent for their growth on him ; and man, 

 as he can both sow and plant them, might have been 

 left thus to provide himself with timber as he has been 



