P 
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A. Gray—North American Flora. 337 
‘geographical distribution. With rarest exceptions, plants 
which are common to this country and to Europe ited well 
northward. But on these summits from southern Virginia to 
Carolina, yet nowhere else, we find—undoubtedly indigenous 
and undoubtedly identical with the European species—the 
Lily-of-the- Valley ! 
e given so 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 
posite, especially of Asters and Solidagoes, and of Sunflowers, 
Silphiums, and other Helianthoid Composite 
from the Rocky Mountains to the Mississippi. Westward, the 
Plains grow more and more saline; and Wormwoods and 
Chenopodiaceze of various sorts form the dominant vegetation, 
Some of them sud generis or at least peculiar to the country, 
others identical or congeneric with those of the steppes o 
horthern Asia. Along with this common campestrine vegeta- 
ion, 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 con- 
tinent from north to south; their flanks wooded, but not ot 
80,—chiefly with Pines and Firs of very few species, and wit 
