CHAPTER II 



GENERAL STRUCTURE AND WORK OF PLANTS ^ 



5. Introductory. Any one of our most familiar plants con- 

 sists of rcjots, stem, leaves, flowers, and fruits containing 

 seeds. Each of these parts is usually distinct (Fig. 1). Each 

 does one or more particular kinds 

 of work, and together they do 

 the work of the whole plant. 

 The plant, therefore, is a complex 

 structure, whose life is depend- 

 ent upon the work of its different 

 parts. 



6. Roots and their work: anchor- 

 age. The most obvious work of 

 roots is done ui holding plants 

 in place, or in giving them an- 

 chorage. On steep hillsidjes, on 

 banks of streams, and in shal- 

 low soil «'hich lies upon stone, 

 the amount of anchorage which 

 roots afford is often so small 



Fig. 1. A buttercup (Ranun- 

 culus acris) 



The plant coDsists of roots, stem, 

 leaves, flowers, and seeds. A, the 

 plant, shown about one eighth natu- 

 ral size ; B, cluster of ripened seeds, 

 shown almost natural size; C, a 

 section through one seed, shown 

 almost three times natural size 



1 This chapter presents an outline of a 

 plant as a working machine. It does not 

 include details but gives a general view 

 of the plant and the kind of work that it 

 does. If this outline chapter is studied 

 briefly, later discussions will be more 



easily understood and more profitable than if numerous details are pre- 

 sented first. The chapter should be read carefully by each member of 

 the class and discussed in one or two recitations, or it may be read and 

 discussed by pupils and teacher together. 



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