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OBSERVATIONS ON THE STRUCTDRE OF RECENT AND FOSSIL 



coNiFERiE *. By William Nicol, Esq. Lecturer on Natural 

 Philosophy^ ^c. Communicated by the Author. With three 

 Plates. 



The structure of recent and fossil Coniferae has lately be- 

 come an object of considerable interest on the continent as well 

 as in this country. At different intervals during the last three 

 years, I have paid some attention to the subject, and, from 

 the investigations I have made, it would appear that much 

 still remains to be done. There are several circumstances in 

 the structure both of recent and fossil coniferae, which seem 

 entirely to have escaped the notice of those who have lately 

 written on the subject, and which, had they been known, would 

 have saved the authors the trouble of forming from a few hand 

 specimens of fossil wood, genera said to be totally different from 

 any of the recent Coniferae. To pronounce with certainty whe- 

 ther a fossil conifera be essentially different from any known in- 

 dividual of the recent kind, it would be requisite to have a 

 thorough knowledge of the structure at least of all the different 

 tribes of recent coniferae ; and yet several distinct fossil genera 

 have been indicated by a person who has examined, and that too 

 very superficially, only three slices of three recent pines, differ- 

 ing not essentially from one another. Before I attempt to in- 

 dicate the points of agreement and disagreement between cer- 

 tmn fossil and recent coniferae, it seems right to premise a ^ew ob- 

 servations relating to the general structure of the latter, as seen 

 both in the transverse and longitudinal sections. 



In the transverse section^ by far the greater part of the Coni- 

 ferae present distinct annual layers. These often vary consider- 

 ably in their relative breadths. In general, however, they are 

 broadest towards the centre, and gradually diminish in that re- 

 spect towards the surface. This may be seen in many of the 

 pine tribe. In a planted Pinus sylvestris, for instance, from 

 Invercauld, in Aberdeenshire, eighty years old, from the pith to 

 the distance of one inch there were only four annual layers. At 



• Read before the Wernerian Society on Saturday, 14th December 1833. 



