VOLUME XXVI NUMBER 3 
BOTANICAL Gazer Ge 
SEPTEMBER 17898 
THE ORIGIN OF GYMNOSPERMS AND THE SEED 
HA 
fe: 
Joun M. COULTER. 
INTRODUCTORY. 
THE most difficult as well as the most fascinating problem in 
connection with any group is its phylogeny. The data upon 
which we base opinions concerning phylogeny are never suffi- 
_ cient, but such opinions usually stimulate research and are nec- 
essary to progress. Any statement dealing with this problem 
is merely an expression of our knowledge of comparative mor- 
phology, and of our judgment concerning the phylogenetic 
importance of certain structures. 
To my mind, the most conspicuous error in many schemes 
of phylogeny is the tendency to focus attention upon very few 
structures. It may be that the structures selected are the most 
significant, but the organism is a plexus of structures, and must 
be considered in its totality. Very different structures have 
been laid hold of by the processes of evolution, and it may not 
be possible to relate the resulting forms properly upon the basis 
of any one or two structures. A conspicuous example is fur- 
nished by the liverworts, in which one line gave special atten- 
tion to the structure of its gametophyte body, another to the 
* Address of the retiring President of the Botanical Society of America, delivered 
at Boston, August 19, 1897. 
ies 153 
