HO W PLANTS GET THEIR CARBON FOOD. 77 



In vaucheria, a branched thread-like alga, the chlorophyll bodies 

 are oval in outline. This form of the chlorophyll body is that 

 which is common to many of the green algae, and also occurs 

 in the mosses, liverworts, ferns, and the higher plants. It is a 

 more or less rounded, oval, flattened body. 



Demonstration 25. 



141. Chlorophyll bodies in leaves. — If it is desired to demonstrate the 

 chlorophyll bodies the teacher can make free-hand sections from fresh leaves 

 of a begonia, or from some other plant. In figure 60 are shown the chloro- 

 phyll bodies in the leaf of the ivy. 



Fig. 60. 



Section of ivy leaf, palisade cells above, loose parenchyma, with large intercellular spaces 



in centre. Epidermal cells on either edge, with no chlorophyll bodies. 



142. Chlorophyll. — The chlorophyll is a coloring substance 

 which resides in the chlorophyll body. It can be extracted from 

 the body by the use of alcohol. The body is a plastid of a 

 proteid nature, widely distributed in many plants. The plastid 

 when not exposed to light is usually colorless, when exposed to 

 light it often becomes green; while in the roots of the carrot 

 and in the petals of some flowers it possesses other colors. 

 When it is colorless it is called a leucoplast, when green a 

 chloroplast, and when yellow, red, etc., a chromoplast. 



143. Where starch is first formed. — The starch is first 

 formed in the chlorophyll bodies. The chlorophyll absorbs 



