14 



THE PLANT CELL. 



y;™ 3. a. Two cells from the leaf of Vallisneria : the left-hand one shows 



cell- walls and the peripheral layer of protoplasm in which are seen the 

 nucleus and chloroplasts. The arrows show the direction of rotation 

 of the protoplasm ; the central clear space is the " central vacuole." 

 The right-hand cell shows the younger cell and chloroplasts containing 

 granules of starch in their interior in process of formation, b. Forma- 

 tion of starch-granules in chloroplasts in a cell of Begonia leaf. 

 c, Formation of starch-granules in chloroplasts of a cell of Vallisneria 

 leaf. 



