156 



PHYSIOLOGICAL BOTANY. 



CHAPTER II. 



TISSUES. 



396. Parenchyma is a tissue composed of short 

 cells, usually with intercellular spaces among them, 

 and is the foundation of vegetable structure. All cells 

 may be regarded as modifications of parenchyma ; the 

 various markings and forms being due to alterations 

 which go on by degrees to fit them for the functions 

 they are to exercise in the tissues of the plant. 



397. In the lower plants the entire individual con- 

 sists of parenchyma, and it is found throughout the 

 structure of the higher 



plants, mingled and in- 

 terlaced with other tis- 

 sue, especially in their 

 green parts. Fig. 501 

 is a microscopic view 

 of a thin slice of the 

 rhizome of Sanguina- 

 ria Canadensis, mag- 

 nified to 100 diame- 

 ters; the cells are un- 



der pressure, and vary 

 *_ , . . , 



greatly in SIZe and. 



shape, and have a bun- 



dle of wood-cells imbedded among them. For forms 



and size of cells see No. 385 ; also see Figs. 480-482. 



398. Prosenchyma is the generic name of the 

 elongated, painted cells or fibers without intercellular 

 spaces that form plant tissues. 



gection of the rh i Z ome.of Bloodroot ; a, a, a bundle of 



