CHAPTER XXXIX 

 THE GREEN PLANT 



Among the wonders of the world are the plant food- 

 factories that exist all about us in countless number. 

 Driven by the power of the sun, the green plants of gar- 

 den, field and orchard work incessantly during the growing 

 season that we may live. 



From air, water and soil, they gather their supplies. In 

 their green leaf laboratories they manufacture food starch 

 or sugar and the proteins that are eaten by man and ani- 

 mals. These they store away in leaf, stem, seed and root. 



From green plants we get the fruit and vegetables and 

 nuts we eat, and the grains we grind into meal or flour. 

 They furnish certain medicines as well, and aid us in other 

 ways. Our knowledge of our surroundings should surely 

 include the life and working processes of plants. 



In a general way plants may be divided into two classes 

 those which produce seeds and those which do not. In the seed- 

 producing class are included trees like the elm, maple, and hick- 

 ory; shrubs like the raspberry, currant, and barberry; and herbs 

 like peppermint, sage, and daisy. Among the plants that do not 

 produce seeds are ferns, mosses, seaweeds, and various forms of 

 fungi, such as mushrooms and puff balls. 



The Green Plant. In the green foliage plants with which 

 we are most familiar, whether tree, shrub or herb, the principal 

 parts are the leaf, stem, and root. These are the organs by which 

 the plant relates itself to the external world, and by which it car- 

 ries on its life processes. All these parts are composed of cells. 



To demonstrate that the plant is composed of cells, its tissues 

 should be examined by the aid of the compound microscope. By 

 mounting and examining cross sections of a young bean seedling, 

 the inner scales of an onion, or some other growing part, the 

 cell structure may be observed. The cell wall and the proto- 

 plasm, which consists of the nucleus and the cytoplasm, may be 



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