2 THE STUDY OF PLANTS 



upon plants or upon plant-eating animals, it follows that if 

 it were not for plants the whole animal kingdom, ourselves 

 included, would soon starve. So too in the matter of clothing 

 we depend partly upon the plants which yield cotton, flax, 

 and similar materials, and partly upon those plant-fed ani- 

 mals which give us silk, wool, and leather. Forests yield the 

 chief materials for ships and other means of transportation, 

 for houses, furniture, and innumeral)le utensils. The fuel 

 which cooks our food, heats our dwellings, and drives the 

 machinery of factories, ships, and locomotives, comes either 

 from plants recently alive or from coal-plants which died 

 long ages ago and were buried in the earth. In sickness, too, 

 the drugs which allay our suffering and help to cure us, are 

 almost entirely of vegetable origin. So whichever way we 

 turn we find plants serving us in most important ways — 

 feeding us, clothing us, sheltering us, warming us, working 

 for us, and making us well — indeed, our dependence upon 

 them is so constant that we seldom realize how intimately 

 our lives are bound up with theirs. 



4. Human needs and the needs of plants. We must not 

 forget that plants as well as animals are living things growing 

 from infancy to old age, needing food and protection, and 

 bearing offspring. Their various parts may be useful to us, 

 but primarily are of use to the plants themselves. The plant- 

 food which we take for our use, the plant had accumulated 

 for its own purposes. The thorns which make a hedge effect- 

 ive against intruders, serve similarly as a defense to the 

 shrub which bears them. Not onlj' then as contributors to 

 our welfare, but as sharers in the mysterious gift of life, 

 should plants have a profound interest for mankind. How 

 plants obtain their food, how they avoid injury, in what re- 

 spects they are like animals, and how they differ from them — 

 such questions soon press for an answer, and then it is seen 

 that all plants, even the most humble, may have secrets 

 of value to tell us. 



5. How plants are named. Whenever many objects are 

 to be studied and compared, it is necessarj' to have some 

 convenient system of naming them and some method of 

 expressing the various degrees of resemblance and difference 



