U 

 PREFACE. 



THE object of this Manual is to present descriptions of the wild 

 fern-plants and seed-plants of northeastern North America in the light 

 of our present understanding of them and of their interrelationships, 

 accompanied by citations of their known natural distribution, their 

 habitats, and their periods of flowering. 



The area embraced in this study extends from Newfoundland and 

 Labrador to Manitoba, the southern boundary of Virginia, Kentucky 

 and Kansas, and the western boundary of Kansas and Nebraska. 



The work is based largely on the text of the " Illustrated Flora " 

 prepared jointly by the author and Judge Addison Brown, published 

 by Chas. Scribner's Sons, 1896 to 1898, in three volumes, which 

 contain, in addition to the more lengthy descriptions than are possible 

 in this book, owing to the necessity of issuing it in one volume of 

 convenient size, illustrations of the species described, 4,162 in all. 

 In order to afford ready reference by those using this Manual to figures 

 of the plants, those of the "Illustrated Flora" are here cited by 

 number at the beginning of each description [I. F. fig. 2042]. 



During the time which has elapsed since the publication of " Illus- 

 trated Flora" a number of additional species have been made known 

 within the area included in both works, and descriptions of these have 

 been incorporated into this Manual in so far as they are understood 

 by me. 



In order to meet present requirements in a text book and to bring 

 our botany into closer relationship with procedure in other natural 

 sciences, all measurements are given in the metric system. For the 

 convenience of those not yet wholly familiar with this system the fol- 

 lowing table of approximate equivalents will be useful : 



METRIC. ENGLISH. 



millimetre (mm.) one-half line 



centimetre (cm.) two-fifths inch 



decimetre (dm.) four inches (3.94) 



metre (m. ) 3 feet 3.37 inches 



ENGLISH. METRIC. 



line 2 millimetres 



inch 2.5 centimetres 



foot 3 decimetres 



