THE STETTCTITKE OF STEMS. 



227 



FIG. 398. 



EXERCISE LXX. 

 Stalk of Monocotyledons. 



The embryo of the monocotyledon is entirely cel- 

 lulai before germination. Growth commences by 

 the elongation of these cells, and the gradual forma- 

 tion of fibro-vascular bundles. At first the bundles 

 are few, and disposed much as in young dicotyle- 

 dons, but, in proportion as the 

 leaves develop, these bundles 

 multiply, and are distributed, 

 without apparent order, all 

 through the cellular tissue; 

 they are, however, much more 

 numerous and solid as they 

 approach the circumference of 

 the stalk. Make an horizontal 

 section of the stem of a corn- 

 stalk, and compare it with Fig. 



398, where the dots (F) represent woody bundles, and 

 the spaces (M) represent cellular tissue. 



FIG. 899. 



If you examine one of these bundles under the 

 microscope, you will find it presenting an aspect like 



