88 THE ROYAL SOCIETY OF CANADA 
Fig. 21.—Pinus banksiana. Cross section of a medullary ray, m.r. from the 
pith to the bast, ph., showing how the ray gave rise to a vertical strand of cells con- 
taining a resin canal, r.c., x 140. 
Fig. 22.—Pinus strobus. Cross section showing a broad medullary ray ex- 
tending from the first year’s summer wood to the bast. The canal in the bast is 
very large and is at the border of the primary and secondary cortex. x 248. 
Fig. 23.—Pinus banksiana. Radial section from phloem. ph. to protoxylem, 
pr. x., showing how a medullary ray, m.r. furnishes cells to a strand of vertical 
parenchyma cells, pa. s. x 248. 
Fig. 24.—Pinus banksiana. Radial section showing how two medullary rays, 
m.r. give off cells to a vertical strand, pa. s., containing a resin canal. x 372. 
Fig. 25.—Pinus banksiana. Radial section showing connection between a 
resin canal, r.c. and medullary ray, m.r., and one in a vertical strand of parenchyma 
cells, pa. s. x 372. 
Fig. 26.—Pinus banksiana. Radial section showing some of the medullary 
ray elements extending vertically and forming part of parenchyma strand. x 372. 
Fig. 27.—Pinus strobus. Cross section showing a large aggregate of paren- 
chyma in which three canals, r.c., are present, the cavities separated by two par- 
enchyma cells which would probably be ruptured later on and thus give one large 
canal. x 372. 
