PREFACE. 



PAET y. 



In the Preface to Part IV. it was stated that Part V. would include 

 the ferns and their allies and also the Musci and Hepaticse. The 

 addendum to the Parts already published had grown so large, however 

 that it was thought better to change our expressed intention, and in 

 the Part now issued — which completes Volume II. — we include an 

 addendum bringing the Parts already published up to date. Part VI. 

 will be published during the ensuing year, and it will include the 

 Characeee, Musci, and Hepaticse, about 1000 species in all. 



Since the publication of Part IV., we have made collections on 

 Prince Edward Island, and on the mainland of British Columbia, as far 

 east as the summit of the Gold Range ; Dr. G. M. Dawson collected in 

 British Columbia in 1888-9, and Jas. M. Macoun on the Athabasca, 

 Clearwater, and Upper Churchill rivers in 1888, the results of these 

 collections have been embodied in this Part. A number of collectors 

 whose names will appear in the addendum have assisted me with notes 

 and specimens, and to them hearty thanks are returned, and it is 

 hoped that they and others will continue the good work. Communi- 

 cation has been kept up with specialists both in Europe and America, 

 and the addendum will show the good results obtained. 



Dr. Serene Watson has examined many critical species, and has been 

 of great assistance in many instances. Dr. N. L. Britton, of Columbia 

 College, New York, has critically examined numerous genera, and is at 

 present at work on others. Prof. Trelease, Director of the Shaw 

 School of Botany, St. Louis, has examined our Geraniacese and vari- 

 ous difKcult genera, and Pi'ofessoi'S Coulter and Eose the whole of our 

 TJmbelliferaB, adding many new species and changing considerably the 



