CHAPTER XIII 
PTERIDOPHYTES 
LESSONS LI, LIT, AND LIII 
The study of a true fern 
Any ordinary fern, such as the bracken fern (Pieris 
aquilina), or the maidenhair fern (Adiantum pedatum), 
will furnish good material for this work. A few weeks be- 
fore this study is begun some fern spores should be sown 
on damp earth in a vessel that should be kept covered in 
order that a regular temperature and moisture may be main- 
tained. These spores develop into very small gametophyte 
plant bodies. Upon these bodies gametes are produced, 
and from the oospore formed from them the sporophyte 
grows. The sporophyte is the part of the plant usually 
called the fern. 
A. THE GAMETOPHYTE. 
1. The vegetative body.—Note the green covering made 
upon the soil by the young plants. See whether you can 
distinguish any separate gametophyte plants. The older 
ones are thin heart-shaped bodies, while the younger have 
not yet assumed this form. Mount some of the youngest 
material and note how the gametophyte develops by study- 
ing and drawing the following stages: 
(a) Cases where the spore is beginning to germinate. 
Can you determine where the first rhizoid 
arises? Does the very young gametophyte 
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