CHLOROPLASTS AND CHLOROPHYLL 



105 



FIG. 115. Upper epidermis and palisade cells of 

 a buttercup leaf 



A, section perpendicular to upper surface; B, exte- 

 rior view of upper surface with palisade cells seen 

 through epidermis ; e, epidermis ; p, palisade cells. 

 Much magnified. After Bonnier and Sablon 



walnut leaf about 

 300,000 per square 

 inch of the lower 

 epidermis. 



124. The meso- 

 phyll ; chloroplasts ; 

 chlorophyll. The 

 mesophyll appears to 

 the naked eye of a 

 uniform green, but 

 under the microscope 

 its cells are seen to 

 contain many green 

 structures called chlorophyll bodies or chloroplasts (" chlorophyll" 

 meaning leaf green and " chloroplast " meaning molded out of 

 green material). The color of the leaf, as well as that of green 

 stems and other parts of the plant body, is due to these. A 



chloroplast is usually, in seed plants and 



in the higher spore plants, of an ellipsoidal 



form or lens-shaped 



a-nd somewhat 



translucent. Its 



color is due to a 



green substance, 



FIG 116. Passage of a soM)le in alcohol 

 fibro-vascular bundle 



from stem to leaf of b ^t not in water, 

 a buttercup (diagram- known as cllloro- 



matic) 



phyll. 



FIG. 117. Diagram of 



125. Woody tis- distribution of fibro- 



vascular bundles in the 



sue in leaves. The leafstalk of a buttercup 

 veins of leaves con- 



s, stem; 10, woody part of 

 bundle ; b, sieve cells of 

 bundle. After Bonnier 

 and Sablon 



e, epidermis ; iv, woody 

 part of bundle; b, sieve 

 cells of bundle ; /, fibrous 

 layer on outer part of 



of the stem of the plant. Indeed, these bundle. Magnified. 



,,,..,, ,. .,, 



bundles m the lear are continuous with 



sist of fibro-vascular bundles containing 

 wood fibers and vessels much like those 



After Bonnier and Sa- 



