SURROUNDINGS OF THE HOME 263 



SUMMARY 



Any knowledge of trees to be satisfactory and complete must be 

 gained by personal acquaintance with them. The use of a "key" for 

 their identification presupposes some knowledge of trees, and is not 

 a substitute for first-hand studies of them. 



A "key" tells what to look for, and how quickly and sharply to differ- 

 entiate between characteristics of trees that are alike in many respects. 

 Good pictures of trees, their leaves, flowers, and fruits, are a great aid 

 in their identification when met in woodland, roadside, and nursery. 



School studies of the leaves, buds, flowers, manner of branching, 

 kind of bark, etc., of some few trees make possible the recognition of 

 other trees whose characteristics are noted as different from those 

 studied. 



Shrubs, evergreens, and ornamental trees on lawns and in parks 

 should be included in any list of tree acquaintances. 



SOME PLANT STUDIES 



Any knowledge of the common plants of garden and farm 

 and roadside, though it be of the most general nature, makes 

 apparent the fact that their parts include roots, stem (trunk 

 and branches), leaves, and flowers. So far as the plant 

 economy is concerned flowers and fruit have for an immediate 

 end the maintenance of the species so that plants shall not 

 become extinct. The root, stem, and leaf are directly con- 

 cerned in the growth and nourishment of the living plant. 

 It may be considered that the chief purpose of the stem of the 

 plant whether of the largest tree or the most insignificant 

 weed of the field, is to secure the largest 'exposure of leaf 

 surface to air and sunlight. The stem of a leaf (petiole), 

 and its framework of midrib and veins, serves a like purpose. 



To the botanist the leaves of a plant are so many labora- 

 tories, and to the economist so many factories, whence comes 

 the food supply of mankind. All things we eat come from 

 plants. Just how this is accomplished is discussed in another 

 lesson. Plants alone can take as raw materials carbon di- 

 oxide gas from the air, and soil water which has in it in solu- 



