1915] SIFTON—BARS OF SANIO 403 
Fig. 4 is from the cone axis of Araucaria Bidwilli and shows the 
structures referred to by JEFFREY as occurring there. Here again, 
in the upper part of the figure, the wall has been partly cut away. 
The photograph is at the same magnification as fig. 3, and on com- 
parison it will be seen that the characters of the bars in the two 
are identical. Here also they invariably cling closely to the pit 
borders and extend only across the width of a single pit. In 
almost every case the forking is plainly seen. A very favorable 
place for observing this is in the left hand tracheid at about the 
center of the figure. Near the top of this tracheid and in the 
majority of cases in the other two, the pits are so closely approxi- 
mated horizontally, owing to the multiseriate character of the 
pitting, that the ends of the forks of adjacent bars meet, so that 
only more or less trapeziform lighter areas are seen between them. 
At one place, indeed, below the center of the middle tracheid, even 
this is not shown. It is quite evident, however, that this is not 
a case of a single bar passing across two pits, but of the application 
of two bars to each other, end to end. This is more evident from 
the section than from the photograph, for in it a light area similar 
to those shown in the series above, though not so pronounced, is 
visible. 
There are, therefore, bars in the primitive region of Cycas exactly 
comparable to those in the araucarian cone axis. This, as JEFFREY 
recognized, makes their presence in the araucarian cone axis value- 
less as an argument in favor of abietinean ancestry of the Arau- 
carineae. Indeed, the evidence of a reverse relationship is apparent 
from a study of the characters of the ‘‘bar’’ in the different regions 
of the Abietineae themselves. 
The typical condition in old stem wood of the Abietineae is 
illustrated in fig. 2, a radial section of Abies amabilis. Where the 
pits are closely approximated in vertical series, as for example in 
the left tracheid of the figure or in the lower part of the tracheid 
to the right, the “rims” unite to form bars. Where the pits 
are scattered, as in the central part of the middle tracheid, each 
’’ stands by itself. In neither case, however, are the ‘“‘rims”’ 
closely appressed to the pit borders, as is always true in the arau- 
carian and cycad form. They are not, moreover, limited in length 
