16 



COLLEGE BOTANY 



many of our important industries. The growth is both internal 

 (intussusception) and external (apposition). The animal cell 

 wall differs from the plant cell wall in that it usually 

 contains nitrogen. 



Cell Contents. In addition to the living protoplasm, the 



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FIG. 6. Typical plant cells, (a) Diagrammatic drawing showing parts of a cell; (6) cell 

 from stamen hair of Tradescantia showing movement of protoplasm; (c) palisade cell from 

 leaf showing nucleus and chloroplasts; (d) cell of Spirogyra showing nucleus and chloroplasts. 



cell may contain many other bodies and compounds, some 

 of which are protoplasmic in character, while others are 

 non-protoplasmic. 



The most important protoplasmic bodies of the cell (Fig. 6) 

 are: (1) The cytoplasm, to which we) have already referred. (2) 



