58 GROWTH AND WORK OF PLANTS 



branous projection at the junction of blade and sheath, and it 

 partly surrounds the stem. 



97. Gross structure of the corn stem as seen in cross 

 section. The outer hard layer is called the rind. The soft 

 pithy portion of the interior forms the bulk of the stem. Scat- 

 tered in the pith are minute firmer and more compact points as 

 seen in cross section. If old corn stalks which have lain in the 

 field during winter and a part of the following season are cut 

 through the rind and the pith within broken, these firm portions 

 are apt to pull out in the form of fibers as shown in fig. 53. 

 " Stalks" of celery (the petioles of the leaves) are excellent to 

 show these bundles which make old or tough celery "stringy." 



Fig. S3- 

 Broken corn stalk, showing nbro-vascular bundles. 



98. Fibro-vascular bundles. These fibrous portions are 

 made up of several kinds of elongated cells united in the form of 

 a bundle. Some of the cells are slender, have thick walls, and 

 overlapping ends. They are woody fibers and give strength to 

 the bundle. There are other elongated cells which are tubular 

 and are joined end to end to form vessels. The water which 

 passes from the roots to the leaves largely passes through these 

 vessels, hence the term vascular. There are other kinds of cells 

 too, but the bundle takes its name from these two sorts and is 



