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 tune 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. 



