FLOWERLESS PLANTS 



441 



still lying as they fell, and we have a picture of what nature 

 would be without the beneficent work of fungi ; that is, 

 they cause decay. They return to Mother Earth the mat- 

 ter which has lived, that it may live again. Without them 

 all available food in the world would soon be locked up in 

 dead forms, and new life would be impossible. 



This is a rather knotty point ; but it may be attacked in a direct 

 and simple manner by asking the children : " Where does our food 

 come from ? What is its last 

 or ultimate source ? " They 

 will say: "It comes from 

 plants, wheat, corn, fruits, 

 vegetables; and animals, 

 beef, mutton, pork, fish, fowl, 

 ,etc." " But where do the 

 animals that we eat obtain 

 their food ? " " It comes 

 from the plants ; so that, in 

 the last analysis, the food of 

 animals, man included, comes 

 from plants, directly or in- 

 directly." The next question 

 is: "Where, then, do the 

 plants get their food?" 

 " With the help of sunshine 

 green plants derive the food 

 with which they build up 



leaves and grains and fruits and woods from the soluble materials 

 in the soil and from the invisible matters in the air." Now comes the 

 crucial question : " Can a green plant grow in wood, or leaves, or 

 fresh meat, z'.^., in the undecayed body of an animal or plant ? 

 Have any of the class ever seen a green plant, not a parasite, 

 growing in this way?" 



The diagram, Fig. 178, will make these relations plain. In their 

 elementary physiology lessons the children may have had simple 



NITRATES 

 FIG. 178. THE CIRCLE OF PROTEID FOOD 



MATERIALS 



, n, represents free nitrogen drawn in 

 from the air 



