THE WALLFLOWER 33 



of altered cells of this kind in various organs of 

 such plants as the Wallflower, more especially 

 in the wood. 



b. Special Contents of Cells 



Many other structures are found in cells besides 

 protoplasm, nucleus, and cell-wall. Some of these we 

 will not trouble about until we come to them in de- 

 scribing the internal structure of our types. One or 

 two, however, are so important that they must be 

 mentioned at once. 



a. Chlorophyll- Granules 



If we examine, under the microscope, a living cell 

 from the green succulent parts of the leaf or stem, we 

 shall find, embedded in the protoplasm, a number of 

 round bodies of a bright green colour (see Figs. 19, 

 p. 42, and 26, p. 69). If we soak the leaf or stem in 

 alcohol, and then examine its cells, we shall find 

 that the green colour has gone, the colouring matter 

 having been dissolved by the alcohol, which becomes 

 of a dark green colour in consequence. The round 

 bodies themselves remain, however, unaltered in size 

 and shape, though now colourless. The green colour- 

 ing matter is chlorophyll, the round granules which 

 contain it are the chlorophyll granules or corpuscles. 

 Protoplasmic granules of this kind are called plastids. 

 The chlorophyll granules consist of protoplasm, rather 

 denser and firmer than the ordinary protoplasm of 

 the cell, and saturated by the green colouring 

 matter. All green parts of plants owe their colour 

 3 



