CHAPTER X 
FERNS 
106. Summary.—Before studying the ferns, it is well to 
note the progress that has been made by the plants previ- 
ously considered. It has been said that the Alge and 
Fungi together form the first great division of the plant 
kingdom, the Thallophytes. The liverworts and mosses 
together form the second great division, called the Bryo- 
phytes, 2 name meaning “moss plants.’”? The ferns intro- 
duce the third great division, called the Pteridophytes, which 
means “fern plants.” A summary of the contributions 
made by the Bryophytes to the progress of plants is as 
follows: 
(1) The land hatit.—The Bryophytes establish green 
plants upon the land, and as a consequence begin to develop 
those structures that the new conditions demand. 
(2) Alternation of generations.—A life-history consisting 
of alternating sexual (gametophyte) and sexless (sporo- 
phyte) generations is finally established, although it is in- 
dicated in the life-histories of certain Thallophytes. 
(3) Gametophyte the chlorophyll generation.—In the alter- 
nation the gametophyte generation develops the chloro- 
plasts for food manufacture, and on this account is the con- 
spicuous generation. When a mossor a liverwort is spoken 
of, therefore, the gametophyte is usually referred to. 
(4) Sporophyte dependent.—The sporophyte in the Bry- 
ophytes is dependent upon the gametophyte for food, and 
hence remains attached to it. Only by the Anthoceros forms 
has a partial independence of the sporophyte been attained. 
13 183 
