CHAPTER VIII 
LIVERWORTS 
90. Summary.—As an introduction to liverworts it is 
well to state the most important facts in reference to the 
Alge and Fungi. The Alge and Fungi together consti- 
tute the first great division of the plant kingdom, known 
as Thallophytes. The name means “thallus plants,” and 
“thallus”? means a body usually prostrate and having no 
special vegetative organs as leaves and roots. Such a 
definition cannot be very rigid, for some Alge cannot be 
said to have strictly thallus bodies, and in the higher groups 
thallus bodies also occur; but the name is a convenient one 
to apply to all plants below the liverworts. 
As the study of the higher plants is begun, the important 
progress made by the Thallophytes must be kept clearly in 
mind, for the liverworts start with this progress behind 
them. The important progress may be stated as follows: 
(1) Increasing complexity of the plant body.—Beginning 
with single isolated cells, the plant body reaches con- 
siderable complexity among the Thallophytes, in the form 
of simple or branching filaments, plates of cells, and masses 
of cells. 
(2) Appearance of spores.—Beginning with reproduction 
by vegetative multiplication, the Thallophytes soon develop 
* special cells for reproduction (spores), and produce them not 
only in abundance but in a variety of methods and forms. 
(3) Appearance of sexual cells.—After ordinary spores 
appear, the Thallophytes also introduce a third form of 
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