A TEXTBOOK OF BOTANY 

 FOR COLLEGES 



INTRODUCTION 



CHAPTER I 

 THE SCOPE AND VALUE OF BOTANICAL STUDY 



THE word BOTANY came originally from the Greek, where 

 it meant simply grass, or herbage, especially that of a pasture. 

 Its meaning, however, has expanded step by step with the 

 progress of knowledge, until now it embraces every kind of 

 scientific inquiry about plants. Thus the scope of the word, 

 as of the science, has indeed become great. In the first 

 place, plants themselves are wonderfully diverse in appear- 

 ance, structure, and habits, for they comprise not only the 

 familiar trees, shrubs, and herbs, with ferns, mosses, and sea- 

 weeds, but also the mushrooms, molds, yeasts, and germs of 

 disease and decay. Furthermore, the number of distinct 

 kinds, or species, is far greater than most people imagine. 

 Of plants having flowers, no less than some 133,000 separate 

 species have already been described and named by botan- 

 ists, while of the flowerless kinds, which reproduce by spores, 

 some 100,000 species are likewise known, making 233,000 in 

 all. ' It is believed, however, that a good many others re- 

 main to be discovered, probably enough to bring up the 

 number of the flowering kinds to 150,000 and of the flower- 

 less to the same number, making at least 300,000 in all. As 

 to the kinds of facts which botanists are trying to discover 

 concerning this multitude of diversified plants, there are 

 no limitations, because no bounds exist to the intellectual 

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