Green Leaves at Work 



95 



In autumn, Nature withdraws the coloring-matter 

 from the chlorophyll bodies, and at last the bodies 

 themselves disintegrate, so that by time the leaf 



a 



FIG. 17. Some common fresh-water algse. (Much magnified.) 



a, Zygnema, with two star-shaped chlorophyll bodies in each cell ; b, Mougeotia, 

 with a single oblong chlorophyll body in each cell; r, Spirogyra, with chloro- 

 phyll bodies in the form of spiral bands. 



falls nothing is left of them but a few yellow 

 granules. 



When a plant which has been growing in the 

 light is subjected to continued darkness, the green 

 pigment fades out of the chlorophyll bodies so 

 that they become pallid, and finally white. Event- 

 ually the little disks or ovals themselves disorgan-. 



