108 BOTANICAL GAZETTE [AUGUST 
as the older forms are more araucarian and the more recent ones 
more like modern Pinaceae, particularly certain Taxodineae and 
Sequolineae. 
Though the argument from resemblance and geological sequence 
is unfavorable to this theory, there are, nevertheless, a great many 
known facts that can be best explained in accordance with it. The 
evidence derived from a study of vestigial structures, recapitula- 
tions, traumatic reversions, and monstrosities largely favors this 
theory, though many facts are known which appear to be incon- 
sistent with it. 
The pitting of the tracheids in the ovulate cones has been inter- 
preted by THomson and JEFFREY in exactly opposite ways. The 
former calls attention to the multiseriate (3-5 rows) cordaitean 
pits of the older wood, and the latter to the uniseriate wood 
of the first few tracheids. To make matters worse, the former 
calls attention to araucarian pitting in abietinean cones and 
roots. This could, of course, be explained as a heritage from 
the cordaiteans. 
The argument from recapitulation is hardly more fortunate. 
- The seedling pine lacks spur shoots, just as does Araucaria, and 
hence spur shoots are not ancestral; but on the other hand the 
seedling Araucaria has abietinean pitting in the earlier annual rings. 
Similarly, wounding an araucarian produces no resin canals, 
though it should if this theory be true; though wounding Brachy- 
phyllum did. In other cases it does recall or induce abietinean 
characters. 
The use that has been made of the bars of Sanio appears to the 
reviewer to fall in a class by itself. From the time of LINNAEUS’ 
classification of flowering plants down to the present many such 
artificial distinctions have been proposed. They have usually 
been short-lived. Inasmuch as a bar of Sanio must have been 
at some time acquired, one would suppose that if you traced 
the ancestral line backward it would gradually fade out. In 
that case there would certainly be Abietineae somewhere along 
the line that lacked this structure. THompson’s discovery of its 
presence in mature secondary wood of modern araucarians renders 
