32 



GROWTH OF THE PLANT 



chlorophyl is located in small bodies called chloroplasts, 

 principally within the cells of the leaves (see Fig. 4, c). 

 Leaves are particularly well adapted to their purpose of 

 absorbing light waves, being broad and flat, thus exposing 

 a large surface to the light. Moreover, they are so distrib- 

 uted that light can fall on them to the best advantage; 

 as can be seen by examining the grouping of leaves on 

 plants — a grapevine for example. 



tDODCDCDCDe^CrDO — a 



Fig. 3 



Fig. 4 



Figs. 3 and 4. — Section of a leaf. Much magnified. 



Fig. 3. — Across the whole leaf, a, epidermis; b, palisade cells showing 

 chloroplasts, c; d, crystals of calcium oxalate; e, spongy parenchyma also 

 showing chloroplasts, c; /, air spaces; g, stoma. 



Fig. 4. — Single cell, c, chloroplasts; s, starch grains; n, nucleus; p, 

 protoplasm. Drawing by C. A. Smith. 



Chlorophyl itself does not develop in the dark. Potato 

 sprouts, for example, that grow in a dark cellar may be of 

 considerable size and small leaves may develop, but they are 



