PART I. 



ORGANOGEAPHY. 



1. If we examine any common plant, such as a Grass, 

 Rose-bush, Willow, or an Oak, three distinct parts will be 

 found, namely : 



I. EOOT. 



II. Stem. 

 III. Leaves, 



2. The Root, or descending axis of the plant, generally 

 grows downwards into the ground, sends out numerous 

 branches, and thus firmly fixes the plant in its position. 

 It also absorbs from the soil water or moisture, which con- 

 tains plant food held in solution. Leaves, or scales repre- 

 senting leaves, are never found on the roots, 



3. The Stem, or ascending axis, generally grows 

 upwards, and furnishes the support for all the parts which 

 grow above ground. It may be herbaceous, — that is, of 

 soft tissue, like the Pansy, — or it may be woody, like the 

 Lilac, or Willow-tree. 



4. The Leaves are inserted on the stem or its branches. 

 They are generally of a deep-green color and flattened 

 shape. Their ofSce is to convert the inorganic food, which 

 has been absorbed by the roots and conveyed to them by 

 the stem, into organic matter. From them more or less 

 watery vapor is continually escaping. 



5. Hairs, or Trichomes, may occur on any part of 

 the plant, as on roots, stems, or leaves. They are mostly 



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