528 BOTANICAL GAZETTE [DECEMBER 
undergoes 2 transverse divisions, the sequence of which could not 
be determined; the lower 2 cells form the stalk and the upper one 
the archegonium proper, agreeing in this repsect with Pallavicinia 
radiculosa, described by CAMPBELL and WILLIAMS (figs. 11,~12). 
Three vertical divisions occur in the archegonium proper, accord- 
ing to the manner of all anacrogynous Jungermanniales, resulting 
in the formation of an inner cell surrounded by 3 primary wall cells, 
2 of which can be seen in a longitudinal section (fig. 12). A trans- 
verse division in the upper part of the inner cell results in the 
formation of a central cell and a cap cell (fig. 13), which later under- 
goes further division, contributing to the development of the neck. 
Following the formation of the cap cell, the central cell divides 
into two nearly equal cells (fig. 14), the upper being the primary 
neck canal cell, and the lower the primary ventral cell. The devel- 
opment of the axial row usually precedes the division of the primary 
ventral cell, although frequently mitoses can be seen in the neck 
cells after the formation of the ventral canal cell and egg (fig. 22). 
In most cases about 10 neck canal cells were seen; sometimes, how- 
ever, as many as 18 are formed (fig. 25). The primary ventral cell, 
by a transverse division, produces a ventral canal cell and egg 
which are almost equal in size (fig. 18). The neck canal cells are 
surrounded by a jacket of 5 cells, although frequently one or more 
of these may divide (fig. 24). 
Very soon after the division of the ventral cell the ventral canal 
cell becomes mucilaginous and finally the entire axial row is broken 
down (figs. 19, 20). The egg nucleus at this stage is very promi- 
nent, the dense nucleolus being surrounded by extremely light 
nucleoplasm. With the preparation of the egg for fertilization, the 
wall of the venter becomes 2-layered, the first divisions occurring 
as the ventral canal cell begins to disorganize. The mature arche- 
gonium is characterized by a rather long slender stalk, a narrow 
venter, and a long twisted neck; it closely resembles an arche- 
gonium of Symphyogyna. 
Just before the older archegonia in a group mature the charac- 
teristic perianth appears immediately within the involucre. It 
attains a height of several cells (fig. 21), but as soon as fertilization 
is effected, it is greatly stimulated, and develops, by basal inter- 
