2 OUTLINES OF PLANT LIFE. 



spected they too are seen to be made up of a great many 

 minute parts, each consisting of a bit of living protoplasm 

 and some other things which it has made. These parts are 

 called cells. (See ^4.) 



Thus, a corn plant has two principal members, a root, below ground, 

 and a shoot above ground. The root consists of many subordinate mem- 

 bers, the roots and the rootlets ; the shoot consists of stem and leaves ; 

 the leaves of sheath and blade, etc. But a duckweed shoot has no dis- 

 tinction of stem and leaf, and only a single root. The pond scums have 

 no members, but consist of a row of cells; while in many diatoms the 

 body is a single cell. 



3. Reproduction. — Every plant must provide for its ov^^n 

 existence. To do this, it must possess means for securing, or 

 for making, and using food. During this feeding period its 

 most striking characteristic is growth. It must also provide 

 before it dies for the production, of new plants of the same 

 kind. When the plant is very simple, both duties must be 

 done by the same cell, but in more complex plants special 

 cells, and in many cases special members, are provided for 

 reproduction. The two processes are sometimes carried on 

 at the same time, but more commonly reproduction occurs at 

 some particular or limited period. 



It is convenient to consider first the form of the plant body 

 and those members which are not concerned in reproduction. 

 Parts I and II therefore, treat of the work and parts of the 

 plant which promote its own life and growth, i.e. the vegeta- 

 tive body. Part III discusses the form and action of the re- 

 productive parts, so far as these can be studied without a 

 microscope. 



4. The cell. — A plant-cell is a minute portion of living 

 matter, called protoplasm, generally surrounded by a mem- 

 brane, called the cell-wall (fig. i). 



The protoplasm is the essential part of the cell. It con- 

 structs the cell-wall. Rarely, if ever, is it uniform through- 



