THE FLORA OF THE PRAIRIES. 585 
of the open prairies, as compared with the herbaceous vege- 
tation of regions to the eastward similarly situated geograph- 
ically, is mostly made up of coarse, large species, and of 
forms peculiar to the prairies. It consists, moreover, prin- 
cipally of a comparatively few predominant forms,—features 
strongly in contrast with those of the neighboring regions. 
The grasses, like.the exogenous species, are also few in spe- 
cies, but coarse and luxuriant, as they are the product of a 
soil of unsurpassed fertility. Yet the flora as a whole is one 
singularly susceptible to the inroads of civilization. Even 
the grazing of cattle for a few years is sufficient to materially 
alter its character. The grasses, according to the testimony 
of early settlers, soon dwindle in size and luxuriance, while 
the relative abundance of the other plants becomes materially 
altered. As already remarked, the breaking and turning of 
the soil at once exterminates a large number of the previ- 
ously dominant species, and instead of lingering as trouble- 
some weeds, the more hardy exotics, that through man's 
influence assume an almost cosmopolitan habitat, usurp their 
places, the cereals, the cultivated grasses and the noxious 
weeds of the old world thoroughly crowding out the original 
occupants of the soil. "With all the beauty and the novelty 
of the primal flora of the prairies, the traveller, after a few 
weeks of constant wandering amid their wilds, is apt soon 
to experience a monotony that becomes wearisome, the full 
degree of which he scarcely realizes till the soft green sward 
and the varied vegetation of cultivated districts again meet 
his eye. 
AMER. NATURALIST, VOL. IV. 74 
