WEEDS 77 
some because it thrives late in the season after the usual 
cultivation of the crops has ceased. Two important 
weeds in blue-grass lawns are crab-grass and annual blue- 
grass. The latter thrives in the spring, making an appear- 
ance pleasing to the eye, but later dies, leaving unsightly 
bare spots. In the same way crab-grass, later in the 
season, leaves brown patches as the plants die. 
105. On the Pacific coast other species of grasses 
become weeds. A very noticeable group are the annual 
species of Bromus. They are of some value as forage 
when young but soon become too dry and prickly from the 
awns of the inflorescence to be palatable. The principal 
species are Bromus commutatus, B. hordeaceus, B. rubens, 
B. tectorum and B. villosus (Par. 260). Another species, 
B. secalinus, the common cheat or chess, is found in grain 
fields throughout the northern United States. The wild 
oat is abundant on the Pacific coast in grain fields and on 
fallow lands, but possesses a mitigating character in that 
it can be used for hay (Par. 239). Several weedy species 
belong to the genus Hordeum, the inflorescence of which 
possesses numerous rough awns that are troublesome 
when mixed with hay. There are three annual species, 
H. pusillum, H.Gussoneanum and H. murinum. The last 
is a common weed in alfalfa fields where it is called fox- 
tail and barley-grass. 
106. Perennial weedy grasses—Of the group that 
lack creeping rhizomes there are few that are troublesome. 
One of the worst of them is Hordeum jubatum, which in 
the West often infests alfalfa fields. It is called squirrel- 
tail-grass, but locally is known as foxtail in Wyoming, 
barley-grass in Utah, and tickle-grass in Nevada. 
Many species become conspicuous in overgrazed pas- 
tures or ranges because not eaten readily by stock. To 
