PREFACE TO THE SECOND EDITION 



The bound copies of the first edition of this Manual were all sold some months 

 ago. During the five years gone by, since the first appearance of the book, a 

 number of new species have been described from the region, and specimens of 

 additional species, introduced from the Eastern United States, from the Pacific 

 Slope, or even from the Old World, ha-y e been collected. Thus have been added 

 to the Flora of the Rocky Mountain Region: 2 families, 17 genera, and 132 

 species. The Flora of flowering plants and ferns contains, therefore, as far as 

 Ivnown now, 1055 genera and 6029 si^ecies. The known ranges of many species 

 have also been extended. In order to carry the work up to date, it was thought 

 best to add to the new issue an appendix of Additions and Corrections and Ex- 

 tension of Ranges. In preparing this appendix, I have received help from the 

 following persons, to whom my thanks are due: Mr. W. A. Dayton and Mr. 

 1. Tide.strom of U. S. Forest Service, Mr. G. E. Osterhout, Prof. E. Bethel and 

 Miss Hazel M. Schmqll, of Colorado, Prof. A. O. Garrett of Utah, and Prof. E. 

 B. Payson of Wyoming. 



P. A. Rydberg. 



The New York Botanical Garden, November, 1922. 



TABLE OF CONTENTS 



Introduction v 



Tables : Abbreviations, Signs and Measurements xii 



Descriptive Flora 



Sperjviatophyta : Key to the Families 1 



Gymnospermae 11 



Angiospermae : Monocotyledones 20 



Dicotyledones , 185 



Pteridophyta 1038 



Appendix 



Summary 1057 



New Genera an Species and New Combinations 1060 



Abbreviations of the Names of Authors 1070 



Glossary 1078 



Index 1088 



Second Appendix 



Additions and Corrections 1111 



Extensions of Ranges 1142 



New Species and New Combinations Published in the Second 



Edition 1143 



Index to the Additions 1144 



iv 



