176 



are far from being adequate, they still represent the only method 

 by which a satisfactory nomenclature can ever be attained, that 

 of international agreement: and the attempt of any nation to 

 herd by itself in these matters cannot hope for any greater success 

 than the proposal of the " f ree-silverites " in the matter of a 

 monetary standard. 



Perhaps a more just estimate of the scope and value of Pro- 

 fessor Henry's work may be attained by comparing it with 

 another manual covering an adjacent field. In 1906 Professor 

 C. V. Piper published a Flora of Washington (Contr. U. S. Nat. 

 Herb., Vol. XI), which still remains in many ways a model of 

 scientific accuracy and thoroughness. Since Washington ad- 

 joins British Columbia on the south, considerable resemblance 

 between the floras of the two regions would be expected, and the 

 majority of the species mentioned in the one manual might with 

 reason be looked for in the other. 



A glance at the map, however, will show that this expectation 

 of similarity must not be carried too far. Washington extends 

 240 miles south of British Columbia; and no tendency in plant- 

 distribution is more marked than the increase in the number of 

 species away from the arctic regions and toward the tropics. 

 The distinctively Californian flora which extends northward 

 through Oregon and into Washington with a steadily diminish- 

 ing number of representatives, seems to have reached its northern- 

 most limit, in the case of the vast majority of species, in the 

 neighborhood of a boundary which coincides more or less roughly 

 with that of southern British Columbia. What may be termed 

 the Alaskan or sub-arctic flora in like manner seems to have 

 reached the limits within which it may be called dominant some- 

 where north of the 49th parallel; and although many of its mem- 

 bers continue southward in the Rockies, this region lies too far 

 eastward of the eastern boundary of W^ashington to have much 

 influence on the flora of that state. 



The exact limits of Henry's manual are not very clearly de- 

 fined to the northward. In his own words, "The region covered 

 is mainly the southern part of the province extending from Van- 

 couver Island to the Rockies, with a rather indefinite northern 



