IMPORTANT RANGE PLANTS. 19 



The plant, being late in maturing and the herbage green and tender 

 throughout the season, is grazed with much relish by all classes of 

 stock from early spring until late autumn. 



It occurs in dense stands only in small isolated patches and conse- 

 quently is not highly important as a range plant. 



Spiked Trisetum. 

 ( Trisetum spicatum.) 



The genus Trisetum belongs to the oat tribe, and is represented by 

 about 8 species in the western United States, most of which occur in 

 the higher mountains. 



The zonal distribution of Trisetum sincatum is typically Hudsonian, 

 though it occurs commonly above timber line and is found to a limited 

 extent on north and east slopes in the Canadian zone. The plant 

 occurs irregularly in scattered stands throughout the upland ranges 

 in exposed situations on well-drained soils. It is frequently asso- 

 ciated with slender hair-grass, but is more deeply rooted. As its habi- 

 tat indicates, spiked trisetum is not readily killed by drought. Most 

 specimens tested were able to regain turgor and, of course, absorb 

 water from the soil until its content was reduced to from 7.5 to 9.5 

 per cent. As a rule the plants died very gradually, probably owing 

 to the highly developed contrivances for protection against rapid 

 transpiration. 



The plant is a perennial of tufted habit with deep and widely spread- 

 ing fibrous roots (Plate XIV). It may usually be recognized by the 

 soft downy pubescence on the sheaths and culms, which has given it 

 the local name "wool grass," although this is a widely variable char- 

 acter, some individuals appearing nearly smooth. Most specimens 

 appear downy silvery white. The culms vary in height from 1 to 2 

 feet. From the crown arise a large number of short, flat, and rather 

 wide basal leaves. The panicle is spikelike and cylindrical in char- 

 acter, somewhat contracted and shiny. The lemma or flowering 

 glume bears on the back a rather inconspicuous, slender, soft, divergent 

 awn. 



The flower stalks appear about July 10, and a month later produc- 

 tion is usually complete. The seeds do not begin to ripen before about 

 August 25, and generally are not all matured by the time inclement 

 weather comes in the fall and prevents further development. As a 

 result, viable seed are produced only on the earliest flowering stalks. 

 In 1907 the seed crop averaged 11 per cent germination, and in 1909, 

 28 per cent. No tests were made in 1908. 



While spiked trisetum occurs in scattered stands, it is widely dis- 

 tributed and furnishes more forage than is ordinarily thought. The 

 leaf blades are eaten in preference to many other species, so that little 



