The Structures and Processes of Stems 127 



Bur.ju 0/ A^n.iLlurc, J'. I. 



Fig. 75. Stripping abaca for fiber. The long • petioles are pulled under toothed 

 knives which scrape the soft tissues from the bundles. Abaca is a monocot, and 

 the fiber is composed of an entire bundle. 



tissue the bundle cannot increase in size, and there can be no 

 growth of the monocot stem through the muhiplication of 

 cambium cells. The dicot bundle, on the other hand, is 

 spoken of as open, because there is a cambium layer between 

 its water-conducting and food-conducting tissues and the 

 bundle can increase in size. The monocot bundle differs 

 further from the dicot bundle, in that its mechanical tissues 

 form a complete sheath about the food and water conducting 

 parts. It is as though the bast of the outer part of the dicot 

 bundle and the wood of the inner part were joined at the sides 

 of the bundle to make a sheath al^out the conducting tissues. 

 The fibers like sisal and Manila hemp, that are derived 

 from the monocots, are usually coarser than the libers derived 

 from dicots, because the monocot fibers are entire bundles, 



