144 T"h^ Great World's Farm 



is merely concealed from view, hidden by other coloring- 

 matter. 



But some plants never have any leaf-green under any 

 circumstances, and therefore, being non-manufacturers, 

 they have to live by the labor of others. Among these 

 are the fungi, which grow and feed entirely upon organic 

 matter, animal or vegetable, and are independent of the 

 light. Mushrooms, for instance, may be grown in cel- 

 lars; toadstools spring up in the night; for their food of 

 all kinds — mineral food, nitrogenous compounds, carbon 

 compounds — has been made ready for them in the light, 

 by the dead vegetable matter upon which they grow. 

 Perhaps it is the fact of their not having any work to do 

 which enables them to grow with such extraordinary 

 rapidity, as they devote all their energies to feeding and 

 increasing in size. The cells of the puff-ball, for instance, 

 multiply at the rate of three or four hundred million in 

 an hour, and the plant will attain the size of a large gourd 

 in a few days. The curious brown bird's-nest orchis is 

 another plant which has no leaf-green, cannot provide its 

 own food, and lives upon dead vegetable matter. 



But there are other plants devoid of leaf-green, which 

 prey, not on the dead, but on the living; sucking their 

 juices, and profiting by their labors in earth and air. 

 Among these may be mentioned the broom-rape, a 

 brown, uncanny-looking plant, which attaches itself to 

 the roots of living plants, clover, and others, and draws 

 all its nourishment from them. 



In one way or another, then, all plants obtain carbon; 

 and when they have to do it by their own exertions they 

 must have leaf-green, and they cannot usually have leaf- 

 green without light, or in any case, without iron. 



