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 Am. 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 

 inermis 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 L. 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 seealinus (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 duooping 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 



