Dec., 1913.] 
The Classification of Plants, XI. 
211 
THE CLASSIFICATION OF PLANTS, XI.* 
John H. Schaffner. 
The various groups of Bryophyta are apparently closely 
related and it is sometimes difficult to tell what characters are 
of phyletic importance. There are no fundamental peculiarities 
or structures which will divide the group into two or three main 
divisions without considerable overlapping of equally important 
structures of another type. Thus one is compelled in certain 
cases to delimit classes and orders on trivial or rather unimportant 
structures. Nevertheless, the complexity of the group as a whole 
demands that it should be divided into a number of classes. 
The homologies of the various organs are quite evident among 
themselves and also when compared with the plants immediately 
above; yet we often find a very illogical terminology and a set 
of names applied to the various structures which makes comparison 
with other phyla impossible until special explanations have been 
made. If we apply a morphological terminology to the mosses 
and liverworts similar to that used in other groups no difficulty 
of presentation is experienced. Such an attempt has worked well 
for the writer in dealing with large numbers of students in general 
botany. 
The synopsis of the Bryophyta given below segregates the 
main groups and attempts to arrange them in phyletic series. 
SYNOPSIS OF THE CLASSES OF BRYOPHYTA. 
A. Archegonia not sunken in the plant body; sporophvte without 
definite intercallary growth between the foot and sporan¬ 
gium. 
I. Gametophyte thalloid or with stem and scales, the scales 
always without a midrib; sporophvte without a stalk or 
differentiated into foot, stalk and sporangium mostly 
with elaters, never with a columella, opening irregularly or 
by a lid, or mostly by four valves. Hepaticae. Liver¬ 
worts. 
II. Gametophyte with stem and scales, the scales mostly 
with a midrib; sporophvte usually with a solid stem; 
sporangium mostly opening by a lid (operculum) or if 
opening by slits or valves, not with elaters; columella 
present in the sporangium, complete or occasionally 
incomplete; archegonium usually developing as a calyptra 
after fertilization. 
* Contributed from the Botanical Laboratory of Ohio State University, 
No. 78. 
