1868.] HOOKER — ARCTIC FLORA. 361 



be seen that there is scarcely one of them that has not been treated 

 as a synonym, variety, subspecies, form, or lusus, by one or more very 

 able and experienced botanists, some of them by many. Further- 

 more, it is curious to observe how much the botanists of each coun- 

 try do to a considerable extent agree amongst themselves as to the 

 specific identity or difference of the same forms — the Scandinavian 

 agreeing with Fries, the German with Koch, and the American 

 with Hooker's l Flora Boreali- Americana' ; also to observe, that in 

 all these cases the authors I quote are independent observers, and 

 not copyers or followers. I think this fact indicates that the same 

 plant presents a different aspect (probably obliterated in drying) 

 in each country. This observation is consonant with what we 

 know of the tendency of all species to run into local varieties in 

 isolated areas, which varieties are often appreciable to the eye or 

 to the touch, but are not expressable by words. 



Of the 7G2 species enumerated, I have compared arctic or boreal 

 specimens of all but a few which I have indicated in the appended 

 notes, and in most cases I have compared specimens from all the 

 southern areas indicated ; but I do not pretend to have made such 

 a critical study of all the grouped species, or of all those belonging 

 to difficult genera (as Draba, Poa, etc.), as to enable me to say 

 that I have given all their distribution, or satisfied myself of all 

 their affinities and differences. There are, on the contrary, fully 

 60 genera out of the 323 arctic ones enumerated, each of which 

 requires careful monographing, and months of study before the 

 limits, systematic and geographical, of its common European 

 species can be ascertained. In two of the largest and most 

 difficult of these I have been indebted to others ; namely, to Dr. 

 Boott, who has revised my list of Carices, and to Dr. Andersson of 

 Stockholm, who has drawn up that of the Salices: each has 

 extensively modified the conclusions of his predecessors in arctic 

 botany ; quite as much or more so than I have done in any genus, 

 and I have every confidence in their judgment. Colonel Munro 

 has twice revised the list of grasses with a like result. In these 

 important genera, therefore, the groups express the opinions of 

 these acute botanists as to the limits of the species. 



With regard to the probable completeness of our knowledge of 

 the flowering plants of the arctic zone, I think it is pretty certain 

 that there are few or no new species to be discovered. The 

 collectors in the numerous voyages undertaken since 1847 in 

 search of the Franklin expedition have not added one species to 



