[PKNHALLOw] NOTES ON TERTIARY PLANTS 43 



applied.^ The opinion was expressed that the wood might belong 

 to one of the Sequoias represented in the beds by leaves and fruit. A 

 more detailed study of this wood enables us to determine to what extent 

 these references are justified. 



Transverse. — The growth rings are rather narrow and distinguished by a nar- 

 row but rather dense zone of summer wood, which is rather abruptly 

 defined from the spring wood. The tracheids of the latter are very 

 large, squarish and thin-walled, while in the former the 4—9 rows 

 of cells are thick walled. The entire aspect of the section is such as 

 to immediately call to mind the similar structure of Sequoia semper- 

 virens, while it also recalls the structure of S. langsdorfii from Van- 

 couver and the Queen Charlotte Islands. " In the latter, however, 

 a point of difference is to be noted in the conspicuously thicker walls 

 of the tracheids of the spring wood. Resin cells are numerous and 

 to be at once recognized by their uniformly dark color, due to the 

 abundance of the somewhat massive resin they contain. These cells 

 are found abundantly throughout the growth ring, but most numer- 

 ously on the outer face of the summer wood. Here again we get a 

 point of very strong resemblance to S. sempervirens, but of diver- 

 gence from S. langsdorfii. 



No evidence is presented by the specimens in transverse section 

 to show that resin canals formed a part of the original structure, and 

 in this there is a well defined deviation from the characteristics of both 

 ^. sempervirens and S. langsdorfii, in both of which imperfectly 

 'organized resin canals appear on the outer face of the summer wood, 

 though not with great or regular frequency. In one or two instances, 

 •within the summer wood of a single growth ring, small, rounded spaces 

 were to be seen, strongly suggestive of former resin canals. They were 

 'about 116 microns in diameter, or equal to about two or three tracheids, 

 'There was absolutely no evidence of structure, however; the edges of 

 the openings showed that structures of the size of canals could not have 

 'occupied the spaces, although upon comparison with the resin canals in 

 S. sempervirens, the openings were found to be about equal to the 

 average size of those structures, inclusive of the epithelial cells. Fur- 

 ther examination ■disclosed the fact that similar openings in Cupressus 

 could be referred to local crystallization and consequent obliteration 

 of structure, and when this was joined to the additional fact that the 

 longitudinal sections gave no evidence of resin canals, but exhibited 

 local areas of crystallization which could be correlated with those of 

 the transverse section, the conclusion that resin canals were absent 

 became fully justified. 



* B. N. A. Bound. Comm., 1875, App. A, 331. 

 =' Trans. R. Soc. Can., VIII., iv., 1S02, 44. 



