100 GENERAL BIOLOGY 



Make a careful drawing of some of the cells of this region. 



Within the cortex, and making up the greater part of 

 the rhizome, is the living tissue, called parenchyma or pith. 

 What is the shape of the cells? How are they joined to- 

 gether? Is there protoplasm within these cells? Are there 

 any bodies within the protoplasm which might be dead 

 substances as food? If fresh sections are available treat 

 with iodine solution and determine whether starch is present. 



Make drawings of the parenchyma cells. 



Scattered through the parenchyma are two large masses 

 and several smaller masses of brownish cells, the sclerenchyma. 

 Is there any definite arrangement to these masses? Com- 

 pare the shape and the grouping of the cells with that of 

 the parenchyma. Is it similar to the parenchyma? Is 

 the cell wall like that of the parenchyma cells? Is proto- 

 plasm present? Do these cells resemble more the paren- 

 chyma or the cortex? These cells are developed from the 

 parenchyma cells by the formation of lignin or wood, and 

 they serve to form a framework for rigidity and support. 

 Is the structure apparently adapted for this? Why would 

 the parenchyma not serve this purpose. 



Make a drawing of the cells of this tissue. 



Oval or circular patches are scattered through the rhizome 

 and are known as nbro-vascular bundles. These bundles 

 anastomose and form a sort of network through the rhizome 

 and frond, through which liquids are conducted from place 

 to place. Study one of the bundles carefully and make 

 out the following: 



1. Bundle sheath, around the bundle. 



2. Phloem sheath, parenchyma like cells containing proto- 

 plasm and starch. 



3. Bast Fibers. Small cells with protoplasm. 



4. Sieve Tubes. Large thin walled cells. 



