28 BULLETIN 545, U. S. DEPARTMENT OF AGRICULTURE. 



throughout the season, though it does not seem to be consumed with 

 the same eagerness as many other species. 



Mountain Wheat Grass. 

 (Agropyron violaceum.) 



Mountain wheat grass resembles in general appearance cultivated 

 wheat, though the two are not closely related botanically. Like 

 big bunch grass, this species is a densely tufted perennial with deep 

 and spreading roots. It is readily distinguishable from the former 

 species, however, by its awnless spikelets or the presence of a slight 

 rudimentary awn on the lemma. The leaves are unusually numerous, 

 basal, flat, and somewhat rough, about half the length of the culms, 

 the latter attaining a height of from 1 to 2 feet. The spikes are 

 slender and short, the lower (empty) glumes being conspicuously 

 three-nerved (PL XXII). 



Though common in both the Canadian and Arctic-alpine zones, 

 this species reaches its best development in the Hudsonian zone. As 

 would be expected from the extensive development of the root 

 system, it is best adapted to soils of medium moisture content. It 

 inhabits open exposed situations, and is usually associated with big 

 bunch grass, mountain bunch grass, and little bluegrass. In ecologi- 

 cal requirements it resembles these species closely. In the drought 

 tests it did not wilt beyond recovery until the soil water dropped 

 to between 6 and 7.5 per cent. 



The flower stalks begin to show during the last week of July or 

 first days of August, and production is for the most part complete 

 within 3 weeks after their first appearance. As a rule the seeds are 

 ripened from about August 20 to September 1. Dissemination takes 

 place almost immediately after maturity. 



As a rule, the vitality of the seed of most of the species growing in 

 the Hudsonian and Arctic-alpine zones reaching maturity on or 

 before September 1 is high, and in this respect mountain wheat 

 grass is no exception. In 1907, a very poor seed year for mountain 

 wheat grass, there was an average germination of 78 and in 1908 

 and 1909, respectively, an average of 96 and 82.5 per cent. From 

 these figures it would be expected that this species is regenerating 

 in favorable localities. Observations show that this is true where 

 the seed crop is worked into the soil through grazing or otherwise, 

 but where the surface layer is undisturbed the seeds, which are 

 large and have no awns on the flowering scales to bore them into 

 the ground, do not germinate. 



Mountain wheat grass is greatly relished by all classes of stock. 

 Growth starts promptly in the spring, and the plant remains green 

 and palatable until late in the fall. It is eaten with the greatest relish 



