THE SPOROPHYTE OF SPHAGNUM SUBSECUNDUM 
could not be discovered. No fungus could be observed on or about the 
archegonia in these particular cases. The cells which had not disintegrated 
were apparently normal in every respect. It was unquestionably similar 
observations which led Schimper to state that it is the lower part of the 
young embryo which finally produces the sporophyte, the upper part 
dying and being resorbed. 
Summary 
The main points of this paper may be summarized as follows : 
1 . The fertilized egg divides by a horizontal wall into two approximately 
equal cells. A filament of cells — 6 or 7 in number — is usually formed 
before longitudinal divisions occur. 
2. In the material studied the wall which separates the cells at the 
two-celled stage cannot be traced with certainty in the older stages, hence 
no exact statement can be made as to the contribution of each of these two 
cells in the development of the sporophyte. 
3. It is reasonably certain that apical growth occurs. 
4. The basal portion of the young sporophyte may have walls appearing 
in a regular or in an irregular order. As a result of the former process there 
is developed a long, slender type of young sporophyte; as a result of the 
latter a shorter, bulbous type. 
5. The number of primary segments, i.e., segments formed by walls 
transverse to the axis of the archegonium, has not been found to exceed 
twelve. 
6. A considerable number of very young sporophytes show basipetal 
disintegration. 
Conclusions 
Much has been made of the striking character common to the Antho- 
cerotales and the Sphagnales as contrasted with the remaining members of 
the Bryophyta — namely, the origin of the sporogenous tissue from the 
endothecium. The writer desires to point out the wide difference in early 
embryogeny. The general history in the Anthocerotales is the formation of 
an unequal quadrant, the two upper cells being somewhat larger than the 
basal ones. This stands in sharp contrast to the filament of six or seven 
cells produced in Sphagnum. An examination of the early embryogeny 
of the Bryophyta shows that the closest approach in this respect to the 
condition in Sphagnum is to be found among the Jungermanniales. Here 
a filament of three cells formed before the appearance of vertical walls is 
not uncommon. 
If similarity in early embryogeny is significant in determining phylogeny, 
it must be evident that in this one respect Sphagnum shows a closer rela- 
tionship to the Jungermanniales than to any other group of the Bryophyta 
Department of Botany, 
University of Wisconsin 
