THALLOPHYTES: ALG^E 225 
The great distinction between these two divisions of 
Thallophytes is that the Algae contain chlorophyll and the 
Fungi do not. Chlorophyll is the characteristic green color- 
ing matter found in plants, the word meaning " leaf green." 
It may be thought that to use this coloring material as the 
basis of such an important division is somewhat superficial, 
but it should be known that the presence of chlorophyll gives 
a peculiar power one which affects the whole structure 
of the nutritive body and the habit of life. The presence 
of chlorophyll means that the plant can make its own food, 
can live independent of other plants and animals. Algae, 
therefore, are the independent Thallophytes, so far as their 
food is concerned, for they can manufacture it out of the 
inorganic materials about them. 
The Fungi, on the other hand, contain no chlorophyll, 
can not manufacture food from inorganic material, and 
hence must obtain it already manufactured by plants or 
animals. In this sense they are dependent upon other or- 
ganisms, and this dependence has led to great changes in 
structure and habit of life. 
It is supposed that Fungi have descended from Algae 
that is, that they were once Algae, which gradually acquired 
the habit of obtaining food already manufactured, lost their 
chlorophyll, and became absolutely dependent and more or 
less modified in structure. Fungi may be regarded, there- 
fore, as reduced relatives of the Algae, of equal rank so far 
as birth and structure go, but of very different habits. 
ALG^E 
154. General characters. As already defined, Algae are 
Thallophytes which contain chlorophyll, and are therefore 
able to manufacture food from inorganic material. They 
are known in general as "seaweeds," although there are 
fresh-water forms as well as marine. They are exceedingly 
variable in size, ranging from forms visible only by means 
