92 CIRCULATION AND USES OF FOOD BY PLANTS 



DiCotyledoa Monocotyledon 



e e 



Observations. — 

 Compare stems of a 

 dicotyledon (apple) 

 and a monocotyledon 

 (corn) ; also, leaves of 

 dicotyledons, oak, elm, 

 or chestnut with those 

 of monocotyledons, 

 lily, grass, or corn. 



Conclusion. — 1. 

 Make table comparing 

 differences of (1) stems, 

 (2) leaves, (3) seeds. 

 Note the difference in 

 position in the stem 

 of pith and bundles. 

 (Use lens.) 



2. Where is the 

 woody part in a dicoty- 

 ledon? Where in a 

 monocotyledon? 



Problem 76: To 



study the structure 

 of a woody stein. 



Materials. — Small 

 cross sections of apple, 

 horse chestnut, or any 

 other woody stem. 

 Page 98, Civic Biol- 



ogy- 



Observations. — In a cross section of apple or any other woody 

 twig note: 1. The central soft part, the pith. 2. The wood. 

 3. The hark. Can you find radiating lines, medullary rays, in the 

 wood? How many layers of bark do you see? 



^f 



em 



c, cotyledon ; e, endosperm ; h, hypocotyl ; p, plu- 

 mule ; fh, fibrovascular bundles. 



Note. — Between the wood and the bark is a rapidly growing layer called the 

 cambium. 



