[pENHALLow] NOTES ON TERTIARY PLANTS 4S 



the fusiform type. These are quite as abundant as in any of the 

 Coniferae where they normally occur, and as in other cases, they 

 are characterized by the presence of a central resin canal. In their 

 general aspect they sugg-est the type common to the genus Pinus, in 

 that the central tract broadens out somewhat abruptly, the cells are 

 all thin walled, and the resin canal of the central tract contains an 

 abundance of thin-walled thyloses. No similar structure is to be 

 found in any of the existing species of Sequoia. The only approach 

 to it is to be found in S. sempervirens, where certain of the medullary 

 rays broaden out into a fusiform shape by the development of cells 

 which become 2-seriate through the central portion, but in none of 

 the numerous specimens of this species examined by me, have I yet 

 found anything approaching the possible structure of a resin canal. 

 The 2-seriate character of the ordinary rays, is also a feature of 

 the wood now under discussion, and this feature makes the resem- 

 blance to S. sempervirens much stronger, though it by no means 

 establishes identity. 



Under the name of Sequoia magniiica, Dr. F. H. Knowlton has 

 described a fossil species from the Yellowstone National Park ^ which 

 so closely resembles S. sempervirens that Dr. Knowlton says it is 

 " hardly to be separated by any well defined characters," and that 

 there can be " no doubt that the living redwood is the direct descendant 

 of this remarkable tree that was once so abundant in the Yellowstone 

 National Park." - S. burgessii resembles this fossil in many essential 

 features, but differs from it in the very essential fact that it has con- 

 spicuous resin canals in the medullary rays, which Dr. Knowlton 

 informs me are certainly wanting in S. magnifica. Under these cir- 

 cumstances it is necessary to distinguish the specimen from the Great 

 Valley Group by a separate name, and for this purpose it seems appro- 

 priate that the work of my friend. Dr. T. J. W. Burgess, who served 

 ar- Botanist to the British North American Boundary Commission, and 

 who did valuable work in studying the existing îiora of that region, 

 should be recognized. The complete diagnosis of Sequoia burgessii 

 as now known is as follows: — 



Transverse. — Growth rings chiefly narrow but variable, the rather narrow but 

 variable summer wood dense, the transition from the spring wood 

 abrupt. Tracheids of the spring wood large, squarish and thin 

 walled. Resin canals wholly wanting. Resin cells numerous 

 throughout the growth ring, but especially on the outer face of the 

 summer wood; with dark, massive resin. Medullary rays chiefly one 

 cell wide, occasionally broader and bearing a resin canal with large 

 thyloses. 



Radial. — Bordered pits large, in 1-2 rows. Medullary rays often with a large 

 resin canal bearing thyloses; the cells all of one kind, the upper and 



' U. S. Geol. Surv., Mon. XXXIII., Part II., 761, pi. CXI. 

 =" Ihid. 762. 



