[pENHALLow] N. AMERICAN TAXACEiE AND CONIFER.E 35 



The whole number of species iind varieties included in our ])resent 

 studies is eighty-nine, representing fourteen genera. 



The present work involves no claim to originality beyond the method 

 of woi-king out the details. Fully twenty years ago, having due regard for 

 the work already accomplished by various investigators, DeBary gave a 

 clear exposition of the general basis upon which such a classification 

 might be constructed, thereby summarizing the results already reached 

 b}' (iuppert, Ilartig, Ncirdlinger and others.' 



N^otwithstanding the work already referred to, little interest apj)ears 

 to have centred in this line of investigation until 1880, when the Vienna 

 Acadeni}' pi'oposed as a subject for the Baumgartner prize of 1,000 florins 

 "The microscopical investigation of the wood of living and fossil plants," 

 the special object of the investigation being to ascertain characters where- 

 by it would be possible to determine the genus and species with certainty, 

 from microscopical sections. Since then the literature of the subject has 

 increased considerably, the various papers either dealing with the subject 

 as a whole or treating of some special aspect of the question, and to these 

 reference will be made as occasion requires. 



The Coniferœ, as a whole, have been so well investigated, that the 

 characteristic features of their various anatomical elements are well 

 known, and require little or no special discussion at this time. Such 

 considerations, therefore, do not properly constitute a part of the present 

 paper, in which we are more directly concerned with the application of 

 anatomical facts to questions of taxonomy. It naturally follows from 

 this that, when anatomical elements possess no diagnostic value, they do 

 not form an element of the present discussion. 



For purposes of comparison it has been held of importance that all 

 nieasurements and drawings should be made under as nearly identical 

 conditions as possible. All determinations of structure, therefore, with 

 one exception to be noted in another place, have been made by means of 

 Zeiss A and D objectives and ocular 4. All measurements have been made 

 under identical conditions, while all the drawings, executed with the same 

 combination and by means of a Zeiss camera, are upon a uniform scale 

 of 280 diameters. 



In the pi'epai'ation of material for examination, as also in the exam- 

 ination itself, certain precautions have been observed, and to these it will 

 be desirable to draw attention for the benefit of those who may have had 

 but limited experience in this line of work. JS'o complete diagnosis can 

 be made from a single section. It is quite true that we may with cer- 

 tainty, and from a simple examination of a tangential section, distinguish 

 Douglas fir from all other woods, and that we may with equal certainty 

 separate Pinm and Ficea from one another and from nearly all other gen- 



1 Comp, Anat. of Phan. and Ferns. 



