72 



STRUCTURE OF HIGHER PLANTS 







l^ocra, Cells 



In cross section, a certain leaf will show cells 

 arranged in an orderly fashion. One part of the 

 leaf contains many air spaces through which gases 

 are exchanged with the active surrounding cells. 



ocir 



All cells need energy to 

 carry on their work. Each 

 cell takes in oxygen, oxi- 

 dizes the food distributed 

 to it, and gives off carbon 

 dioxide and some water. 

 These materials may be 

 e>ia«rinis distributed either through 

 the vascular system or by 

 passing from cell to cell. 

 The entire plant grows by 

 the growth and division 

 of the individual cells. Reproduction of the plant is too compli- 

 cated to discuss here, but it will be found later that it, too, is due 

 to the division of certain cells. 



In this chapter, the shape of plant cells has been considered. 

 It is by their shape, organic nature, and arrangement that they are 

 fitted to perform certain functions. Each cell of higher plants 

 contains the structures discussed in a resting plant cell. It is by 

 the coordination of all these cells that the entire plant functions. 



Questions 



1. Make an outline of the specializations in higher plants, using the 

 headings (a) name of tissue, (6) function, (c) adaptation to function. 



2. Name the structure in a higher plant corresponding in function 

 to each structure observed in a cell of Spirog^Ta. 



Supplementary Readings 



Coulter, Barnes, and Cowles, A Textbook of Botany (American Book Co.), 



Vol. I. 

 Holman, R. M., and Robbins, W. W., A Textbook of General Botany (John 



Wiley & Sons, Inc.). 

 Gager, C. S., General Botany (Blakiston's Son & Co.). 



