CHAPTER VIII 



TAXONOMY 



DIVISION I. THALLOPHYTA 



Plants, the greater number of which, consist of a thallus, a body 

 undifferentiated into root, stem or leaf. The group nearest to the 

 beginning of the plant kingdom presenting forms showing rudi- 

 mentary structures which are modified through division of labor, dif- 

 ferentiation, etc., in higher groups. 



SUBDIVISION I. PROTOPHYTA (SCHIZOPHYTA) 



A large assemblage of " fission plants" comprising the bacteria 

 and blue-green algae. In the simplest types no nucleus is present, 

 but as we arise in scale through the bacteria and blue-green algae, 

 there is to be observed an open granular, gradually growing to a 

 crescentic, chromatin mass that may be called a nucleus. A common 

 method of asexual reproduction is possessed by these plants whereby 

 the cell cleaves or splits into two parts, each of which then becomes 

 a separate and independent organism. 



I. SCHIZOMYCETES BACTERIA 



Bacteria are minute, unicellular, colorless, rarely weakly red or 

 green colored, non-nucleate vegetable organisms destitute of chloro- 

 phyll. They serve as agents of decay and fermentation and are 

 frequently employed in industrial processes. According to the vari- 

 ous phenomena they produce, they may be classified as follows (a) 

 Zymogens producing fermentation; (b) Aerogens producing gas; (c) 

 Photogens producing light; (d) Chromogens producing color; (e) 

 Saprogens, producing putrefaction ; (/) Pathogens, producing disease. 



Physical Appearance of Bacterial Colonies and Individual Forms. 

 Because of their minute size a space the size of a pinhead may 



219 



