654 BOTANICAL INFORMATION. 
Platte, Arkansas and the Colorado on the West, it comprises 
most part of the higher plains of thesouthern slope of the Rocky 
Mountains, from an approximate elevation of 4,000, down to 
1,200 feet; and follows the new red sandstone formation to 
every point of the compass; northward to the Saskatchawan 
and Lake Winnipeg; south to the Wachita of upper Ar- 
kansas river; east to the mouth of Big Sioux river of the 
Upper Missouri, and even to the Des-Moines river of the 
Upper Mississippi; and, lastly, westward to the Walla- 
Walla, a small tributary of the great Columbia and Oregon 
territory. 
With so great a variety of elevation and extent of territory; — — 
(through nearly 20° of latitude and longitude) it will be - I 
necessary to subdivide the whole into 4 subregions, according 
to their principal features. "The one prevailing feature is that 
of a comparative barrenness and desert-like appearance, some 
small parts of river-valleys only excepted. 
General character of the vegelation.—Kast and westward 
the limits of the Cupulifere and Conifere.—Small groves and - 
thickets of Salicinee !—Eleagnee, conspicuous in the two 
genera Eleagnus and Shephardia !—Station for the greater 
proportion of N. American Chenopodiacee in North America! 
—Hordeaceæ, prominent among the Graminee.—Cichora- — 
cee, Chrysopsidee and Senecionidee among the Compo- 
site !—Representatives of families: Allium striatum, Caly- 
menia angustifolia, Cnicus undulatus, Viola Nuttallii, Bar- 
tonia ornata, Solanum flavidum, Heliotropium Curassavicum, 
Callistegia paradoxa, Triglochin maritimum, Beckmannia, 
Rhus trifoliata !—Disappeared families of the last region: 
Aceree, Chloridee, Malvacee ! — Disappeared conspicuous — 
genera of the former region : Allionia, Delphinium, Carduus, 
Sida, Anemone, Phlox, Lupinus, Polygala, Mammillaria, Echi- 
nacea, Gaura, Melanthium, Cypripedium, Coreopsis, Batschia, — 
Atheropogon, Panicum, Macheranthera, Evolvulus, &c. &c.! — — 
Eleagnus argentea and Shephardia argentea appear in the | 
place of Corylus Americana and Prunus Americana! Amor- 
pha nana in the place of A. canescens. ; o 
