40 EASY LESSONS IN VEGETABLE BIOLOGY. 



CHAPTEE VII. 



PROTOPHYTES, OR THE SIMPLEST FORMS OP PLANTS. 



1. THE simplest form of individual plant life is a 

 particle of living matter inclosed in a membrane or 

 cell-wall. Chap. V, Sec. 4. Such plants are called 

 one-celled. Some of these remain entirely distinct 

 from other cells, others form cell-families (Chap. VI, 

 Sec. 1) in a sort of gelatinous investment, while 

 other kinds form a sort of fiber or rod by the adhesion 

 of cells end to end. As each cell in these different 

 kinds is capable of independent life and growth they 

 are all classed as unicellular. 



2. The green slime which grows on stones or 

 boards in damp places contains many of these one- 

 celled plants. 

 One of the 

 simplest forms 

 is shown in 

 Fig. 15. It is 

 often found 

 in rain-water 

 casks, and is 

 called the Pro- 

 tococcus from 



