182 The American Naturalist. [February, 
mites communis Trin. This grass and cat-tail flags and rushes were 
quite common in the swampy meadows and around the numerous small 
lakes of the sand-hill region. 
Along the valley of Snake Creek I found in addition to those 
already mentioned Andropogon nutans L., Oryzopsis cuspidata Beuth., 
Sporobolus airoides Torr., S. vagineflorus Vasey, S. asperifolius N. & 
M., S. asper Kth., Panicum capillare L., Setaria glauca Beauv., S. 
viridis Beauv., Deyeuxia canadensis Beauv., Distichlis maritima Raf., 
and Spartina cynosuroides Willd. 
In the sand-hills around Alliance the principal grasses are Andropogon 
hallii Hack., A. provincialis Lam., A. nutans L., A. scoparius Michx., 
Sporobolus asper Kunth, Oryzopsis cuspidata Bedth., Bouteloua oligo- 
stachya Torr., Deyeuxia canadensis Beauv., Eragrostis tenuis Gray, 
Stipa comata Trin., and on the higher hills, and particularly noticeable 
on the edge of the “ blow-outs,” Muhlenbergia pungens Thurb. In 
. the clear white sand in the ‘‘blow-outs ” Redfieldia flexuosa Vasey is 
found quite abundantly. 
The best grazing grasses are Gramma and Buffalo-grass. Wild wheat 
grass is good for hay but not for pasture. 
I did not find any Sand-burs. They are not needed, for Mammil- 
laria and other cacti make life a burden. 
From Alliance I went west along Snake Creek valley twelve or fif- 
teen miles, then southwest through the extreme western extension of 
the sand-hills till I struck the old Black Hills trail at the head of Red 
Willow cañon, and thence down the Red Willow southeastward to the 
Platte. ‘The only new find was Munroa squarrosa Torr., on the Platte 
side of the divide. 
From the Camp Clarke, on the Platte, where the old Sidney-Black 
Hills trail crosses the river, I went south to Court House Rock and 
Pumpkin Creek. The rock is a great mass of light brown argilla- 
ceous sandstone, which rises about 300 feet sheer above the valley. 
The ridge stretching westward, of which Court House Rock was 
once a part, at one time bore a forest of pine and cedar. Now there 
are only some stumps and a few scattered trees to show what has been 
before. In the cafions at the foot of Court House were Rhus aro- 
matica Ait. var. trilobata Gr., and a number of woody shrubs and vines. 
On the summit of the rock I found Oryzopsis suspidata Benth., 
Agropyrum glaucum R. & S., Aristida purpurea Nutt., a form with an 
erect culm rising from a mat of convolute wiry radical leaves, Boute- 
loua racemosa Lag., the first that I had seen, B. oligostachya Torr., and 
Muhilenbergia pungens Thurb, 
