Tors}. | BURLINGAM E—ARAUCARIANS Iol 
origin from the abietineous Pityoxylon type.” (4) “This con- 
clusion is entirely confirmed by a consideration of the reproductive 
structures, both sporophytic and gametophytic.” (5) ‘Any 
hypothesis as to the origin of the Coniferales in general must start 
with the Abietineae as the most primitive tribe.”’ 
This theory has received from time to time certain incidental 
criticism in connection with the work of investigators who have 
considered that their results justify other interpretations. A 
number of these have already been mentioned in the presentation 
of the lycopod and cordaitean theory. It is in the nature of things 
that the facts which form the support of one theory are usually the 
facts that refuse to adjust themselves easily to others. Objections 
of this sort have found their proper place in the preceding para- 
graphs. I shall now mention some of the more specific objections 
that have been made. 
It has already been pointed out that the protagonists of the 
lycopod theory hold the ovulate cone of the araucarians to be simple. 
The abietinean theory is circumscribed by the necessity of proving 
itcompound. The weight of opinion, at least so far as numbers go, 
among those who have investigated the subject appears very 
decidedly to favor the idea that the ovulate structures of podocarps 
and araucarians are homologous in structure and simple. It 
appears from the work of EAmes and Srnnort, already quoted 
above, that if the abietinean theory prevails they can be explained 
as a reduction series. On the other hand, if this theory were not in 
question, it appears that most investigators would decide in favor 
of simplicity of structure. Aside from the authors already men- 
tioned, Tison (76) and NoreNn (44) have expressed themselves 
in favor of a simple explanation. 
The writer has in earlier papers called attention to the inade- 
quacy of the explanation offered by JEFFREY and CHRYSLER (36) of 
the more numerous prothallial cells in the gametophytes of podo- 
carps and araucarians. These authors suggested that the greater 
number of these cells might be a coenogenetic adaptation to the 
extensive pollen tube. Aside from the reasons for thinking that the 
tube itself has not undergone any such coenogenetic development 
as this theory suggests (by implication) for the araucarians, it is 
