CHAPTER X 
DIVISION THALLOPHYTA 
Divisions of plants. AJ] living organisms are placed in either 
the plant kingdom or the animal kingdom. The plant kingdom 
is divided into large groups, or divisions, the number and size 
of which vary somewhat according to the opinions of different 
authorities. Thus what some botanists regard as one division 
may be divided into two or more divisions by other authorities. 
For convenience the plant kingdom is divided into four divisions 
in the following discussion. These divisions are Thallophyta, 
Bryophyta, Pteridophyta, and Spermatophyta. 
The Spermatophyta are the seed plants. The Pteridophyta 
consist of the ferns and their allies. The Bryophyta are com- 
osed of the mosses and the mosslike plants called liverworts. 
Thallophyta. ‘The name Thallophyta means plants with thallus 
bodies, that is, not differentiated into stems, roots, and leaves. 
The division Thallophyta is made up of such plants, but to say 
that this division contains all the thallus plants is not exact, 
as some of the liverworts have thallus bodies, while none of 
pthe Bryophyta have true roots. The Thallophyta include the 
bacteria, the alge, the fungi, and the lichens. The alowe are the 
seaweeds and other simply organized water plants that have 
chlorophyll. 
CLASS BACTERIA 
The bacteria are very small and apparently simply organized 
plants. Some of them are so small as to be just within the 
limit of vision of the compound microscope. There are other 
organisms which are so small as to be actually invisible, and 
it may be that some bacteria belong to this class. Most of the 
bacteria are either parasites or saprophytes. 
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