THE 



AMERICAN NATURALIST. 



Vol. XXXVIII. April, igo4. Xn. 448. 



THE ANATOMY OF THE NORTH AMERICAN 

 CONIFERALES TOGETHER WITH CERTAIN 

 EXOTIC SPECIES FROM JAPAN AND 

 AUSTRALASIA. PART I. 



D. P. PENHALLOW. 



The present work had its origin in 1880, in an attemj^t to 

 construct a system of classification for the North American 

 Coniferae, based upon the anatomy of the vascular cylinder of 

 the mature stem. The fundamental idea was that such a classi- 

 fication would prove of great value in the identification of 

 material used for structural purposes, but investigations had not 

 been carried very far when it became manifest that some such 

 arrangement was imperatively demanded in other directions and 

 for purposes of a more strictly scientific character. In entering 

 upon the study of fossil plants it was recognized that the most 

 fruitful source of reliable data must be found in the stem struc- 

 ture. At that time there was little in the wa) of an adecjuate 

 basis for further study of this sort, inasmuch as the current 

 diagnoses of the vascular structure were found in most cases to be 

 singularly inadequate, and often so incorrect as to require exten- 

 243 



