96 MORPHOLOGY 
Conclusions. The life history of the Ricciaceae suggests certain 
important conclusions. The sporophyte is the simplest known among 
FIGS. 212 220. Riccia: development of the archegonium; 212, first division of the 
superficial initial cell, the protruding cell to give rise to the archegonium; 213, the 
three vertical walls (two seen in section) investing an inner cell, the relation between 
the three walls being shown in the cross section, 214; 2i5 > further development of jacket 
cells, completely investing a central cell (first cell of axial row); 216, first division of 
central cell into primary neck canal cell (upper one) and primary ventral cell; 
217, further development of the jacket and axial row, the latter showing the four neck 
canal cells and the ventral cell (lowest and largest); 218, division of the ventral cell to 
produce the ventral canal cell and the egg; 219, a completed archegonium, showing neck 
and venter, and the axial row, consisting of four neck canal cells, a ventral canal cell, 
and an egg; 220, fertilization, showing male and female nuclei fusing in the egg. 
