488 BOTANICAL INFORMATION. 
while the hitherto abundant species of Andropogon and Pol- 
linia disappear to the west. Agrostideæ increase, as also 
Hordeacee ; and the Leguminose and Astragaline prevail in 
the flora. Conspicuous representives may be seen of many 
families, mostly of one genus only! Thus of Liliaceæ, 
Yucca; of Pediculares, Castilleja; of Scrophularine, Pents- 
lemon; of Solanee, Solanum triflorum; of Hydrophyllee, 
Ellisia; of Convolvuli, Evolvulus ; of Cinerocephale, Carduus 
. argyrophyllus, Torr.; of Papaveracee, Argemone; etc. White 
and scarlet are predominant among the herbaceous plants ; 
lilac and purplish colours exist only in the species of Pent- 
stemon. 
The Platte or Nebraska River is shallow and rapid with 
an average breadth of a mile, and presents within this region 
most picturesque scenery from the innumerable small verdant 
islands which appear as if sailing in its rapid stream. Most 
of these islands have at least one tree in their centre, and 
some of them small groves, either of Poplar, Elm or Negundo, 
their luxuriant branches bending in the wind. Along the 
banks scarcely a tree is to be seen, except at the mouths of 
rivers and junctions of rivulets. The thickets of Sali lon- 
gifolia, Amorpha frutescens and Rosa parvifolia, when all in 
bloom, afford a pleasant contrast to the adjoining trackless 
drifting sandy ranges of the valley, formed by local currents 
of wind from the hills. These sandy tracts are the abode of 
Stipa avenacea, St. juncea, Agrostis cryptandra, and the pretty 
Eriocoma; sometimes, on firmer sand, the Crypsis squarrosa 
twines over the surface. Only Stipa avenacea grows densely; — — 
scattered amongst it I found the pretty Machaeranthera, =- 
like Centaury, with us, amongst corn. These different spe- 
cies of Stipa formed the favourite food of our horses, but — 
only before their panicle was developed; as soon asthe  — 
_ Spikelets came out, the animals would not touch this genus, — 
but fed on the Eriocoma. Scattered amongst these sand- 
grasses generally were groups of Cleome integrifolia, Asclepias E 
speciosa, Argemone grandiflora, Culymenia multiflora, and : 5 
