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56G 



UK POUT — 1HK4. 



[ have given. &o much of my time to the botany of the Atlantic border 

 that- I can barely touch upon that of the Western regions. 



Between the wooded country of the Atlantic side of the continent and 

 that of the Pacific side lies a vast extent of plains which are essentially 

 woodless, except where they are traversed by mountain-ehains. The 

 prairies of the Atlantic States bordering the ^Mississippi and of the 

 Winnipeg country shade off into the drier and gradually more saline 

 plains which, wit!-, an e\en and gradual rise, attain an elevation of o,000 

 feet or more where they abut against the Rocky Mountains. Until these 

 are reached (over a space from the Alleghanies westward of about twenty 

 degrees of longitude) the plains are unbroken. To a moderate distance 

 beyond the Mississippi the country must have been in the main naturally 

 ■wooded. There is rainfall enough for forest on these actual prairies. 

 Trees grow fairly well when planted ; they are coming up spontaneously 

 under present opportunities ; and there is reason for thinking that all 

 the prairies east of the Mississippi, and of the Missouri up to Minnesota, 

 have been either greatly extended or were even made treeless under Indian 

 occupation and annual burnings. These prairies are flowery with a good 

 number of characteristic plants, many of them evidently derived from the 

 plains farther west. At this season, the predominant vegetation is of com- 

 positoB, especially of asters and solidagos, and of sunflowers, silphiums, 

 and other helianthoid eomposita\ 



The drier and barer j)lains beyond, clothed with the short biitfalo- 

 grasses, probably never bore trees in their present state, except as now 

 some cottonwoods (i.e., poplars) on the margins of the long rivers which 

 traverse them in their course from the iiocky .Mountains to the Mississippi. 

 Westward, the plains grow more and more saline; and wormwoods and 

 chenopodiaceae of various sorts form the dominant vegetation, some of 

 them sui generis or at least peculiar to the country, others identical or 

 congeneric with those of the steppes of northern Asia. Along with this 

 common campestrine vegetation, there is a large infusion of peculiar 

 American types, which I suppose came from the southward, and to which 

 I will again refer. 



Then come the Rocky Mountains, traversing the whole continent from 

 north to south ; their tlanks wooded, but not richly so, chiefly with pines 

 and firs of very few species, and with a single ubiquitous poplar, their 

 higher crests bearing a well-developed Alpine flora. This is the arctic 

 flora prolonged southward upon the mountains of sufficient elevation, 

 with a certain aduiixture in the lower latitudes of types pertaining to the 

 lower vicinity, 



There are almc'St '201 • Alpine pli;enogamous species now known on the 

 Rocky Mountains ; fully three-quarters of which are Arctic, inchidirg' 

 Alaskan and Grcenlnndian ; and about half of them are known in Europe. 

 Several others are North Asian but not European. Even in that northern 

 poi'tion of the Rocky INlountains which the Association is invited to visit, 

 several Alpine species novel to l']uro[)ean botany may be met with ; and 

 farther south the peculiar forms increase. On the other hand, it is 

 interesting to note how many old-world species extend their range south- 

 ward even to lat. ;jti' or '-ii>°. 



I have not seen the Rocky Mountains in the Dominion ; but I appre- 

 hend that the aspect and character of the forest is Canadian, is mainly 

 coniferous, and composed of very few species. Oaks and other cupuli- 

 ferous trees, which give character to the Atlantic forest, arc entii^ely 



