6 ANATOMY OF THE GYMNOSPERMS 



Two objects have been held in view in the preparation of this 

 work : (i) its application to the needs of the scientific botanist 

 in prosecuting researches either in recent or fossil forms, and 

 (2) its adaptation to the requirements of the practical engineer 

 who may be called upon to recognize material entering into the 

 construction of bridges or other important works. While, there- 

 fore, Part I deals primarily with the anatomy of the stem, dis- 

 cussing such features as are essential to a correct knowledge 

 and interpretation of the systematic portion, it also includes 

 special chapters having a more or less direct bearing upon the 

 practical utility of woods, - - such as may be found in those on the 

 general mode of operation of fungus parasites, the durability of 

 woods under different conditions, and the specific action of decay 

 upon the tissues. Owing to the great extent of ground covered 

 by the subject of timber diseases and the special methods to be 

 employed for their control, and the fact that an adequate discus- 

 sion of these important topics would extend the present work 

 much beyond all reasonable limits, the reader is referred for the 

 treatment of diseases to Tubeuf (72), and for methods of wood 

 preservation to important papers by Flad (20) and Constable 

 (10). If such treatment of the general subject serves to secure 

 a wider constituency among those who are called upon to make 

 large use of valuable woods, one of the larger aims of the 

 present work will have been achieved. 



Part II is based upon the details of Part I, and it relates 

 exclusively to questions of classification and relationship. In 

 attempting to construct a classification of the Coniferales upon 

 the basis of the anatomical characters to be found in the woody 

 portion of the stem, it appeared that there was little to be obtained 

 from the work of previous investigators which could be employed 

 as a satisfactory working basis, since the results recorded by 

 Nordlinger, Hartig, Muller, and others, while of great impor- 

 tance with respect to certain aspects of structure and afford- 

 ing many important suggestions, had not been carried to that 

 point where they could be reduced to any very great practical 

 utility. A survey of the literature of the subject showed that 



