Embryo of Botrychium obliqiium, MiiJiL 
H3 
The Antheridium. 
The gametophyte is monoecious, but there is a good deal of difference 
in the relative number of antheridia and archegonia in different individuals. 
The antheridia usually are produced in considerable numbers upon the 
median ridge, and, as usual, begin to develop before the archegonia. The 
latter as a rule form a row on either side of the antheridial ridge, but are not 
developed upon the ridge itself (Figs. 11, 12). 
The development of the antheridium is very much like that of the other 
species (Figs. 13-15). The mother-cell divides first by a transverse wall into 
an outer, or primary, cover cell, and an inner cell from which the sperm cells 
finally develop. 
Text-fig. 2. A. Median section of an antheridium just before the final division of the 
spermatocytes, x 270. 0 , opercular cell. B. Empty antheridium. x 90. c. Surface view of 
antheridium with triangular opercular cell, x 270. D. Surface view of antheridium with two 
opercular cells, x '90. 
The primary cover cell divides by vertical walls into several cells, in 
which horizontal walls are formed, so that there are two layers of cover 
cells. The horizontal wall is suppressed in one of the cover cells, how- 
ever, and this becomes the opercular cell, where the antheridium opens. 
A second opercular cell is sometimes present (Text-fig. 2 , d), but as a 
rule only one is formed. This opercular cell is destroyed at the time of 
dehiscence. In cross-section the opercular cell is generally four-sided, but 
sometimes it is triangular, as in Ophioglossum (Text-fig. 2, c). 
The first division in the inner cell of the young antheridium may 
be either transverse or vertical, and is next followed by a wall at right 
