GENERA OF GRASSES OF THE UNITED STATES. 25 
nate or awn-tipped. Rescue grass is a native of South America and 
is cultivated occasionally in our Southern States for winter forage. 
The other species of this section are natives of the western half of 
the United States. They are all perennials and have large awned 
spikelets. Bromus carinatus Hook. and Arn. and B. marginatus 
Nees are common on the Pacific coast. They have pubescent or 
scabrous spikelets, the first with an awn longer than the lemma, the 
second with an awn shorter than the lemma. Bromus carinatus often 
appears like an annual, flowering the first year. 
The species of Bromus in which the spikelets are not compressed- 
keeled fall into two rather well-marked groups, perennials and an- 
nuals. The most important species of the first group is Bromus 
imermis Leyss., a European species known also as awnless brome- 
grass, Hungarian brome-grass, smooth brome-grass, and brome-grass. 
It is erect, 2 to 3 feet tall, with creeping rhizomes and narrow, many- 
flowered panicles with erect or ascending branches and smooth nar- 
row spikelets about an inch long, the lemmas acute, awnless, or nearly 
so. Awnless brome-grass is cultivated for hay and pasture in the 
northern portion of the Great Plains from northern Kansas to 
Minnesota and Montana. It is more drought resistant than, timothy 
and in the region mentioned can be grown farther west than that 
species, but does not thrive south of central Kansas. All the other 
perennial species are natives except B. erectus, occasionally intro- 
duced from Europe, and all have distinctly awned lemmas. Bromus 
purgans \. is a common woodland species in the Eastern States. 
This has an open drooping panicle with nearly terete spikelets, the 
lemmas pubescent over the back. The closely allied and equally com- 
mon B. ciliatus L. (fig. 2) differs in having lemmas glabrous on the 
back and pubescent on the margins only. Several species are found 
in the Western States, B. porteri (Coult.) Nash, with close drooping 
panicle and softly pubescent spikelets, being common in the Rocky 
Mountains. 
The group of annuals includes weedy species introduced mostly 
from Europe. The best known of these in the Eastern States is 
Bromus secalinus (fig. 3), chess or cheat, a weed of waste places and 
sometimes infesting grain fields. Formerly it was believed by the 
credulous that under certain conditions wheat changed into chess. 
Chess in a wheat field is due to chess seed in the soil or to chess seed 
in the wheat sown. Chess is a smooth grass 1 to 3 feet tall, with flat 
blades and open drooping panicles of smooth turgid spikelets, the 
lemmas broad and inrolled above, the awn about as long as the lemma. 
Bromus commutatus Schrad. differs in having pubescent sheaths. 
On the Pacific coast the annual species of Bromus have become 
conspicuous. They thrive on all open ground at lower altitudes in 
