1915] SIFTON—BARS OF SANIO 401 
Miss GERRY’S suggestion has been followed in a number of recent 
articles on fossil plants. Miss HoLpDEN (4, 5) has used it in several 
papers. Her statement of the importance of the “rims”’ is even 
stronger than that of Miss Gerry, making their occurrence “by 
far the most reliable criterion for diagnosing coniferous woods 
(5, p. 252). Again, in another paper she speaks still more strongly: 
“Comparative examination of living and fossil forms leads to the 
rejection of all criteria except cellulose bars of Sanio as an infal- 
lible test for tribal affinities” (4, p. 5 
JEFFREY (6) has also attached Aer weight to it, especially 
since his discovery in 1912 of what he considers a vestigial bar 
in the araucarian cone axis. His conclusion from its presence here 
is stated as follows: ‘‘Agathis and Araucaria have obviously come 
from ancestors which, in accordance with the accepted principles 
of comparative anatomy, had . . . . bars of Sanio in their tra- 
cheids’’ (p. 548). The phylogenetic significance which he attached 
to its occurrence in this position figures prominently in his theory 
of the abietinean ancestry of the Araucarineae. Recognizing that 
his conclusion from its occurrence in the araucarian cone axis 
would be invalidated if the same condition were found to occur in 
similar regions of forms such as the cycads, JEFFREY examined the 
primitive regions of Cycas, Zamia, and Ginkgo, but found no evi- 
dence of its presence. He was therefore doubly assured of its 
meaning in the araucarians. 
In connection with some investigations of the wood structure 
in the cycads, I have found a “‘bar’ of Sanio entirely similar to 
that in the araucarians, and since this discovery has such an 
important bearing on the theories above stated, it has been thought 
advisable to publish it separately. 
The material in which the “bars’’ were found is from the petiole 
of Cycas revoluta. The sections of this, as well as all the others 
figured in the plate, were stained in the usual way with a double 
stain of Haidenhain’s iron-hematoxylin and safranin. The bars 
thus appear in the sections as dark bands on a red background and 
Stand out as distinctly as in the photographs. 
*The name “bar” has been retained in this paper for the structure as found in 
Araucaria and Cycas, for considerations to be stated later. 
