vi MORPHOLOGY OF SPERMATOPHYTES 



several times by the authors and their students, certain gaps 

 have been filled up, and an original point of view has been estab- 

 lished. So far as possible, the illustrations are original, and some 

 of the series are more complete than any heretofore published; 

 but illustrations have been reproduced whenever they seem neces- 

 sary to a full understanding of the subject. Those which have 

 been copied are fully credited, and may thus be distinguished 

 from those which are published for the first time in this book. 

 References to figures in the text have not been multiplied, upon 

 the assumption that those who use the book are in the habit of 

 consulting figures. 



One of the chief perplexities in connection with the litera- 

 ture of the subject is the confusing and often misleading ter- 

 minology employed by various authors. Not only have different 

 names been applied to a single morphological structure, but fre- 

 quently the same name has been used for very different struc- 

 tures. This has resulted not only in a confusion of terms, but in 

 greatly obscuring a very simple and consistent morphology. 

 We have attempted to introduce uniformity into the terminology, 

 not by proposing new names, but by selecting from those already 

 current the ones which seem the most appropriate. It is to be 

 hoped that this will aid to a better understanding of morpho- 

 logical equivalents. 



It may be well to call attention to the fact that we close 

 the history of the sporophyte with the appearance of the spore 

 mother cell, rather than with the appearance of the spore. 

 This has seemed to us to be the best defined line of demarcation 

 between the two generations, both on account of the reduction 

 division, and because preceding this division the mother cell 

 passes into a more or less prolonged resting condition. It cer- 

 tainly represents- the greatest break in the continuity of the life 

 history. In this sense, therefore, the sporophyte ends with the 

 appearance of the spore mother cell, and later the gametophyte 

 begins with the reduction division. 



