1915] SIFTON—BARS OF SANIO 405 
specialized in the higher conifers, the original type persisting only 
in the primitive regions, the cone axis and the root. Thus the dis- 
covery of the bar in the cycads has, besides confirming the primitive 
character of this structure in the araucarians, made apparent its . 
significance in the different regions of the Abietineae. 
_This work has been carried on at the suggestion of Professor 
R. B. THomson, to whom I wish to express my indebtedness for — 
his constant assistance. 
UNIVERSITY OF TORONTO 
LITERATURE CITED 
1. GERRY, Miss E., Bars of Sanio in the Coniferales. Ann. Botany 24:119- 
123. Igto. 
2. GOppert, H. R., Monographie der fossilen Coniferen. Leiden. 1850. 
3. a PERCY “ns RusuHtTon, W., Jour. Linn. Soc. Bot. 41: 457-490. 
4. THeiocs. Miss R., Jurassic coniferous woods from Yorkshire. Ann. 
Botany 27:243-254. 1913 
, Fossil plants from eastern Canada. Ann. Botany 27:533-545. 
3. 
6. Jerrrey, E. C., The history, comparative anatomy, and evolution of the 
Araucarioxylon type. Proc. Amer. Acad. 48:531-561. 1912. 
7- SANIO, K., Anatomie der gemeinen Kiefer. Jahrb. Wiss. Bot. 9:50-126. 
1873 
8. Tomson, R. B., On the comparative anatomy and affinities of the Arau- 
carineae. Phil. Trans. Roy. Soc. London B 204:1-50. 1913. 
EXPLANATION OF PLATE XV 
Fic. 1.—Cycas revoluta: petiole; tangential section of primary wood; 
R226: 
Fic. 2.—Abies amabilis: radial section of secondary wood of stem, showing 
“rims” and ‘‘bars” of Sanio; X 225. 
Fic. 3.—Cycas revoluta: a portion of fig. 1 more highly magnified; X 445. 
Fic. 4.—Araucaria Bidwilli: radial section of secondary wood of seed cone 
axis, showing ‘“‘bars’’ of Sanio; 445. 
Fic. 5.—Pinus resinosa: radial section of secondary wood of seed cone 
axis close to the primary wood, showing primitive “rims” of Sanio; X 445. 
Fic. 6.—Pinus Strobus: radial section of secondary wood of root close to 
primary xylem, showing primitive “rims” of Sanio; X 445. 
