FLOWERING PLANTS AND FERNS OF ARIZONA 83 



72. Spikelets all alike, not arranged in fascicle- 74 . 

 73. Lemmas 3-nerved, the nerves usually prominent 

 (74). 

 74. Lemmas glabrous, awnless (75). 



75. Spikelets 3- to several-flowered; lemmas 

 acute or acuminate 6. Ebagrostib. 



75. Spikelets 2-flowered; lemmas truncate, strong- 



ly nerved, brown 7. Catabrosa. 



74. Lemmas densely pubescent on the nerves or 

 callus, mucronate or awned 7*) . 



76. Callus densely bearded; lemmas firm, mu- 



cronate, the nerves glabrous. 



8. Redfieldia. 

 76. Callus glabrous; lemmas membranaceous, 

 densely pubescent on the nerves. 



15. Triodia. 

 73. Lemmas 5-nerved (77). 



77. Lemmas mucronate or awned, keeled at least 

 toward apex (78). 

 78. Spikelets densely clustered toward the ends 

 of the branches; glumes hispid-ciliate on 



the keel 10. Dactylis. 



78. Spikelets not clustered, rather evenly dis- 

 tributed in narrow or open panicles (79). 

 79. Lemmas awned from between the teeth 

 of the minutely bifid apex. 



1. Bromus. 

 79. Lemmas awnless, or awned from the tip. 



2. Festtjca. 



77. Lemmas awnless, usually rounded on the 



back (80). 



80. Glumes papery; upper florets reduced to a 



club-shaped rudiment; spikelets nodding, 



falling entire 14. Melica. 



80. Glumes not papery; upper florets similar to 

 the lower ones (81). 

 81. Nerves of the lemma converging toward 

 the apex; leaf blades with boat-shaped 



tips 5. Poa. 



81. Nerves of the lemma parallel, not con- 

 verging toward the apex (82). 

 82. Nerves faint; plants usually of saline 



soil; low annual 3. Puccixellia. 



82. Nerves prominent; plants of fresh- 

 water marshes; tall perennials. 



4. Glyceria. 



1. BROMUS. Brome 



Annuals or perennials with closed sheaths, flat blades, and open or 

 sometimes rather dense panicles; lemmas keeled or usually rounded 

 on the back, the margins not clasping- the palea, awned from between 

 the teeth of the minutely bifid apex; palea thin, ciliate on the keels, 

 usually shorter than the lemma, adhering to the fruit. 



Bromes, in the young stage, are relished by all classes of livestock, 

 but at maturity the "beards" cause mouth injuries. Among the best 

 Arizona forage species are the mountain bromes (7?. marginatum, B. 

 mrmatus, and B. 'polyanthus) and the fringed brome (B. dliatus). Some 

 of the annual species, such as cheatgrass (B. tectorum) and foxtail 

 brome (B. rube7ts) } are introduced weeds. Smooth brome (B. im rmis) 

 is cultivated for hay and pasture in the northern plains region, and 

 rescuegrass (B. catharticus) is cultivated for winter forage in the 

 southern United States. 



