CHAPTER IV 
ALGE 
ABOVE the Schizophytes and Mycetozoa is a large 
assemblage of plants, sometimes all united under the 
name of Thallophyta, but probably better divided into 
two divisions of equal value, to which the rank of sub- 
kingdom may with propriety be applied. The primary 
division is based upon the presence or absence of 
chlorophyll, and although a few of them which have 
no chlorophyll are structurally similar to certain green 
forms, and possibly to be considered as derived from 
them, most of the forms without chlorophyll differ pro- 
foundly in their structure from all green plants, and 
may properly be relegated to a sub-kingdom of their 
own. To the forms which possess chlorophyll, the 
name of Algze has been given, while those where 
chlorophyll is absent are known as Fungi. The two 
low groups of green plants, — the Protococcaceer and 
Volvocinez, — which were considered in the last chap- 
ter, are usually included with the Algz, and very prop- 
erly so, as they doubtless represent the lowest members 
of the sub-kingdom. 
The Algz are readily divisible into three main divi- 
sions or classes, which are easily distinguished by their 
color. All of them possess chlorophyll, but in two 
of the classes there are other pigments present, giving 
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