14 



Principles of Plant Culture. 



microscope of moderately high power, is seen to be 



B 



made up of numerous little 

 sacks or cavities, more or less 

 clearly defined, called cells. 

 Cells from different beings, or 

 C from different parts of the same 

 being, may vary much in form 



FIG. 1. Showing four indi- j . , -, , 



viduai plants of a species and size, but they are seldom 



of protococcus. A shows a . 



plant before commencing to large enough to be Seen Wlth- 

 divide into other plants. 



B, c and D show how the out magnifying power. Some 



cells divide to form other 



plants. Highly magnified. O f the lowest plants and ani- 



FIG. 2. Part of a filament of a species of Spirogyra, a plant 

 consisting of a single row of cells united at their ends. The 

 places where the cells join are indicated by the vertical lines. 

 Highly magnified. 



mals consist of single 

 cells (Fig. 1). Some of 

 the- lower plants consist 

 of a single row of cells 

 united at the ends (Fig. 

 2 ) . The higher plants and 

 animals are made up of 

 many cells united, and 

 in these, the cells assume 

 different forms and prop- 

 erties in the different or- 

 gans (Fig. 3). In some FIG. 3. Showing cells of the ap- 

 ., , ,. Pie leaf in a section from its up- 



Cases the united Cells may per to its lower surface. Highly 

 magnified. The spaces marked I 

 DC readily separated from ar e cavities between the cells. 



one another, which shows each cell to be more or less 



