20 
Colorado Experiment Station 
(fig. lo), which is twisted at the base, where it joins the body of 
grain, and is more or less bent. The base of the grain is very sharp- 
pointed, and the small barbs on it point upward. Hence, the grain 
may work inward easily, but on account of the direction of the barbs, 
it is impossible for it to work outward, or to be pulled out easily. 
It matures its seed from July 15 to August 15. The mature seed im¬ 
mediately drops to the ground. 
The Western Stipa, or Needle Grass (Stipa comata) bears beards 
that reach a length of 4 to 6 inches. This grass is abundant in sandy 
soil throughout the plains and foot-hill regions. There are a number 
of other species of Stipa, which differ from Needle Grass in having 
beards usually less than 2 inches long. In these, also, the beards are 
twisted and bent, and the grain-base is sharp-pointed, and may in 
some instances work mechanical injur}^ to stock.. One of the very 
common short-bearded Stipas is Vasey’s Stipa-Grass (Stipa vaseyi). 
It is particularly abundant in the foot-hills. It grows from 3 to 6 feet 
high and bears an inflorescence 8 to 18 inches long. The beard on 
the grain is usually bent twice, and twisted to the second bend. 
Wild Oats (Avena fatua) 
This is an annual plant much resembling ordinary cultivated 
oats. It has long, slender stems, and hence it usually stands above 
cultivated oats. It is distinguished further from cultivated sort by 
its strongly bent beard, and the long, reddish-brown hairs at the base 
of the grain. The seeds ripen earlier than those of wheat and oats. 
The seed is barbed. 
Downy Brome-Grass, Awned Brome-Grass, Slender' Chess 
(Bronius tectorum) 
This brome-grass is an annual. It stands i to 2 feet tall. The 
leaves are soft hairy. The flowering head has slender, drooping 
branches. The spikelets (fig. ii) are on very thin stalks; they bear a 
number of seeds. They may become purplish at maturity. Each 
seed has an awn which equals the seed itself in length. 
This plant is becoming increasingly abundant in Colorado, occur¬ 
ring in fields, along roadsides and in waste places. In many locali¬ 
ties it has made its first appearance the last year or two. Up to now 
it has been seen only at lower altitudes. 
The beards on the seeds frequently cause serious injury to stock. 
The bearded seeds work in under the teeth causing inflammation, and 
in some instances a loss of the teeth. 
Wild Barley, Squirrel-Tail Grass (Hordeuvi jubatum) 
In the West, this common grass is an annual or short-lived per¬ 
ennial. It grows from 6 inches to 2^ feet high, in bunches. The 
head is 4 inches long or less, pale green, often purplish. The beards 
on the seed-bearing, and sterile flowers are long, and the flowers are 
surrounded by long beard-like glumes so that the whole head is cov¬ 
ered with long bristles (fig. 12) that are rough and upwardly barbed. 
The head breaks up at maturity and the parts are scattered broadcast. 
vSquirrel-tail grass is common, in alkaline soils, about ponds, 
lakes and reservoirs, along irrigating ditches and streams, in mead- 
