IMPORTANT RANGE PLANTS, 35 
The very nature of the habitat in which elk grass succeeds indi- 
cates its unusual ability to withstand low moisture conditions. The 
soil in which it grows is a coarse gravelly one, which liberates the 
water more readily than finer soils. Drought tests resulted in the 
extensive wilting of all leaf blades of the plant only when the water 
content was reduced to 6.5 per cent, and in some instances slightly 
lower. This places elk grass very near the head of the list in its 
ability to exist under adverse moisture conditions. Flower stalks 
begin appear during the last week in June, and by July 20 practi- 
cally all are out. About the time that the last flower stalks are sent 
up matured seeds are found. By August 15 the seed crop is almost 
entirely ripened and disseminated. The seed has about average 
viability, the tests in 1907 and in the two subsequent seasons showing 
germinations of 6, 26, and 32 per cent, respectively. 
In the forepart of the season elk grass is grazed with a certain 
amount of avidity, though practically every other grass species is 
preferred to it. It is only eaten by sheep up to about August 1, 
unless the stock are starved. After that date the leaves become so 
tough, hard, and fibrous that even horses will not graze it if other 
forage is available. Sheep always scatter widely when feeding upon 
it, doubtless searching for more palatable food. 
Rush. 
(Juncus parryi.) 
Among the several species of rushes found on the highland ranges 
Juncus parryi is commonly met with, and in value is typical of 
other species which are abundant in the region studied. 
Like most rushes of the drier situations, Juncus parryi is tufted, 
and has woody, fibrous, deep-spreading roots capable of withstanding 
an unusual amount of abusive grazing. The stems are thin and wiry, 
from 4 to 10 inches long, and the cylindrical leaves are about half 
the length of the flower stems (Plate XXXIII) ; the inflorescence, 
usually 2 or 3 flowered, is surpassed by a bract similar to the leaves. 
Juncus parryi is confined to the high ranges. In the Hudsonian 
zone it occurs extensively in open, exposed situations on well-drained, 
often poorly disintegrated soils. It is usually associated with elk 
grass (Car ex geyeri) and is just about as drought resistant, the 
specimens studied not wilting beyond recovery until the soil-moisture 
content was reduced to from 5.5 to 7 per cent. Above timber line 
it is found in considerable abundance in association with typical 
alpine species. 
On the lowest areas on which the plant occurs the flower stalks 
begin to show about July 10, and by August 5 nearly all have been 
sent up. Matured seeds are usually not found before August 25. 
