268 



TYPICAL FLOWERING PLANTS 



If we examine under the microscope a portion of the 

 epidermis taken from near the center of an onion bulb, we 



find that it is made up of many 

 small parts, called cells. Every 

 cell consists of living matter 

 (protoplasm) surrounded by a 

 wall. Near the center of each 

 cell is a small spherical body 

 called the nucleus. See page 4. 

 All regions of the plant body 

 are made of such cells, and the 

 cells of each region are adapted 

 to the special work of that re- 



f- v ^^^Sii^^i^^^S sdon. Therefore the cells of a 



3miVfB plant body vary in size and 



shape, but all the cells of any 

 one region are nearly alike. 

 Such a group of similar cells 

 is called a tissue. See page 5. 

 A cross section of a taproot 

 shows the tissues of all the 

 layers in the plant. The cen- 

 tral cylinder contains groups 

 of cells called fibrovascular 

 bundles. Some of these cells 

 overlap in such a way that they 

 make continuous tubes from 

 the root, up through the stem, 

 and into the leaves. In the 

 leaves the vascular bundles are 

 called veins. The cells which 

 carry the liquids present in the plant are to the plant 

 what veins and arteries are to animals. The inner part 

 of a vascular bundle is made up of woody cells and is 



Figure 260. — Sections of 

 Bean Root. 



1, epidermis; 2, cortex; 

 3, central cylinder. 



