2 BOTANICAL GAZETTE [JULY 
classes of facts. The object of this paper is to attempt to set 
forth the principal views and to show on what sort of evidence each 
_ rests. Having gotten at the facts, we may then inquire into the 
relative merits of each sort of evidence and attempt to evaluate 
them. If such an evaluation could be made, we might rescue the 
subject of morphology from the fate of being “cast into outer 
darkness.” Iam very little inclined to think that it will be possible 
for any one investigator to set forth the evidence in a manner to 
satisfy the adherents of all views, but my purpose will be served if 
I shall induce those more competent to take up the subject with the 
serious intention of determining just what principles are generally 
applicable, if there are any, and what are the limitations to which 
various sorts of evidence are subject. 
In a broad way the opinions regarding the origin of the arau- 
carians may be grouped under three heads: (1) the lycopod theory, 
(2) the cordaitean theory, (3) the abietinean theory. In setting 
forth these various theories I shall attempt to present the salient 
facts and opinions of a number of those who have written on the 
subject, but no attempt will be made to present exhaustively the 
facts or even the opinions of any one. It will undoubtedly happen 
that in choosing what seem to me the strongest evidences for the 
different views and the strongest objections to them, I shall be 
unable to escape the effects of personal bias, and still less able to 
choose just as the authors themselves would choose. These are 
objections that cannot be wholly avoided. The best I can do is to 
be as impartial as possible and to beg indulgence in advance for 
the slips that are sure to occur. 
The lycopod theory 
The external resemblance of certain conifers to the lycopods has 
attracted notice from early times. The first serious attempt that 
I have found to set forth the evidence for believing that Coniferales, 
or at least certain of them, have originated from Lycopodiales is 
that of Potonré (47) in 1899. A rather free condensation of his 
statement of this theory and the facts on which it is based is as 
follows: (1) conifers, except possibly Taxaceae, are derived from 
‘*Lepidophyten”’; (2) the ancestor of a cone scale was a leaf that 
