LIFE HISTORY OF THE MALE FERN 71 
malic acid to the mouths of the archegonia of another prothallus, 
and, passing down the canal of each of these, gather around the 
ovum. One, probably the best adapted, fuses with the ovum 
and fertilizes it forming a zygote (odspore) or fertilized egg. This 
completes the gametophyte generation. 
OriGcIn OF NEw SpoROPHYTE PLANT FROM FERTILIZED Eco 
The fertilized egg now divides into hemispheres, then into 
quadrants and again to form eight cells arranged in a spherical 
mass and called octant cells. The octant cells divide to form a 
many celled embryo which shows the following parts: foot rudiment, 
root rudiment, stem or rhizome rudiment, hair rudiments, and first leaf. 
GROWTH OF EMBRYO INTO MaATuRE SpoROPHYTE.—The foot 
rudiment develops into the foot which obtains nourishment from 
Fic. 39.—A, median longitudinal section through immature antheridium, and 
cell of prothallium showing prothallial cell (#), and antheridial wall surrounding a 
number of spermatocytes; B, similar section through mature antheridium and cell 
of prothallium showing fully developed spermatozoids (s.p.) enclosed by wall of 
antheridium (an). Both highly magnified. 
the prothallium, upon which the young sporophyte is for a time 
parasitic. The root rudiment becomes the first root which grows 
-downward into the soil. The stem rudiment becomes a rhizome 
_ which, with the first leaf, turns upward. In a few weeks the 
prothallus decays and the sporophyte is established as an inde- 
pendent plant. More leaves (fronds) and roots are developed 
and ere long continued growth results in the formation of a 
mature sporophyte which presents for examination: (4}.:2 
subterranean stem or rhizome, (2) roots; and (3) aerial fronds, each 
of which consists of a stipe or petiole and a lamina or blade, the 
