PRINCIPAL GROUPS OF PLANTS. 7 



and even more. Some of these are more or less complicated in 

 structure. 



The Thallophytes are subdivided into two important groups, 

 as follows : 



The Algae, plants producing chlorophyll or green cell-contents, 

 and hence capable of manufacturing food from the inorganic 

 substances air and water. 



The Fungi, plants not producing chlorophyll, and hence not 

 capable of forming their own food, but living upon dead or 

 living matter. 



Before considering the Algse proper we will consider two 

 groups which are very simple in structure and whose method of 

 reproduction as well as life history is also very simple; namely, 

 the Blue-green Algae and the Bacteria. The Blue-green Algae are 

 ordinarily classified with the Algae, and the Bacteria are very 

 often grouped with the Fungi. Owing to certain resemblances 

 between these two groups it is convenient to arrange them to- 

 gether under the name Schizophytes, or fission plants. 



SCHIZOPHYTES. 



Characteristics. The name Schizophyta means " fission 

 plants," and is applied to this group because the reproduction is 

 chiefly by means of the division of the cells, which may occur 

 either at the middle of the cell and in one direction, in which 

 case a series of connected cells are formed, or in two or three 

 directions, giving rise to spherical aggregates or colonies. They 

 do not usually contain chromatophores, and the coloring sub- 

 stance, when present, is either uniformly distributed throughout 

 the cell or occurs on the external surface of the protoplasmic 

 content. 



There are two chief groups: the one corresponds to Algae, 

 and, while they do not contain a simple green substance, they are 

 for the most part of a blue-green color, although they may assume 

 various shades of orange, yellow, and brown, even appearing 

 chocolate or purplish-red at times. The second group, correspond- 

 ing to the Fungi, comprises the Bacteria or Schizomycetes, which 

 are distinguished for the most part by being nearly colorless and 

 only occasionally of a reddish or green color. 



