36 POACEAE 



Old sheaths of the innovations neither brown nor papery. 



Basal leaf-sheaths short remaining involute in age; blades 

 of stera-leaves rarely 8 cm. long. 

 Awn short, less than half as long as the lemma; inflores- 

 cence dense and narrow. 9. F. saximontana. 

 Awn long, from nearly equalling to much exceeding the 

 lenuna; inflorescene open. 

 Awn little if at all exceeding the lemma in length; 

 ovary glabrous. ' 

 Leaves scabrous. 10. F. ingrata. 

 Leaves smooth. 11. F. idahoensis. 

 Awn much exceeding the lemma; ovary hispidulous 

 at the apex. 12. F. occidenlalis. 

 Basal sheaths long and becoming flattened in age, often 1 

 dm. long; blades of the stem-leaves over 1 dm. long. 



13. F. arizonica. 

 Pulvini at the bases of the branches of the panicle rather conspicuous ; 

 tufts separable with difficulty. 14. F. viridula. 



Body of the lemma 8-12 mm. long; leaf-blades soon breaking ofl! from the 

 sheath; palet notched at the apex; bunch-grasses. 

 Branches of the panicle spreading or reflexed; spikelets shining; leaves 



smooth beneath. 15. F. allaica. 



Branches of the panicle erect or ascending; spikelets rather dull; leaves 

 very scabrous. 

 Plant 5-1.5 dm. high; basal sheaths long, loose, in age more or less 

 flattened : empty glumes narrowly lanceolate, acuminate ; second 

 glume shorter than the spikelet. 16. F. campestris. 



Plant 3-5 dm. high; basal sheaths usually short and close even m 

 age; empty glumes acute, lanceolate; second glume about equal- 

 ling the spikelet. 17. F. scabrella. 

 Ligules elongate, 4-9 mm. long, acute. 18. F. Thurberi. 

 Leaf-blades all flat, 4 mm. wide or more; pereimials with rootstocks. 



Lemma abruptly acute, not at all keeled. 19. F. elatior. 



Lemma awned or awn-pointed, keeled at least above the middle. 

 Awn or awn-point shorter than the lemma. 



Lemma distinctly 5-nerved; awn from the cleft apex: panicle ciliate. 



20. F. dasyclada. 

 Lemma with indistinct intermediate nerves; awn terminal; panicle not 

 ciliate. 21. F. soroHa. 



Awn longer than the lemma. 22. F. subulata. 



Annuals; stamens usually solitary. 



Spikelets 5-13-flowered; both glumes subulate. 23. F. octoflora. 



Spikelets loosely l-5-flow6red; first glume subulate, the second lanceolate. 



Branches of the shoTt panicle normally divergent, a pulvinus at the base of at 

 least one of them. 

 Spikelets usually 3-5-flowered, only the main branches of the inflorescence 



divergent. 24. F. padflca. 



Spikelets usually 1-3-flowered; all branches divergent or reflexed. 



25. F. reftexa. 

 Branches of the elongated narrow panicle erect and appressed. 



26. F. megalura. 



69. HESPEROCHLOA (Piper) Rydb. l. H. Kingii. 



70. BROMUS L. Brome-guass, Chess, Cheat. 



Second empty glume 5-7-nerved; first empty glume 3-nerved. 

 Lemma compressed-keeled. 



Palet less than three-fourths as long as the lemma, which is scarcely toothed. 

 Sheaths and usually also the blades hairy; lemma pubescent or hispidulous- 

 scabrous. 

 Lemma hispidulous-scabrous. 



Awns 10-15 mm. long. 1. B. Hookerianus. 



Awn 4-6 mm. long. 2. B. Flodmanii. 



Lemma pubescent; awns 4-8 mm. long. 



Lower branches of the panicle 7 cm. long or less, in fruit erect. 



Leaves flat, not canescent. 3. B. breviaristaius. 



Leaves involute, canescent. 4. B. subvelutinus. 



Lower branches of the panicle 1 dm. long or longer, spreading in fruit. 



5. B. lalior. 

 Sheaths and blades glabrous or iftlnutely scabrous. 



Panicle narrow, strict; awn 4-6 mm. long. 6. B. polyanthus. 



Panicle open, spreading and nodding; awn 6-7 mm. long. 



5. B. paniculatus. 

 Palet more than three-fourths as long as the lemma, which is distinctly toothed 

 at the apex. 8. B. unioloides. 



Lemma rounded on the back, broadly elliptic; introduced tufted annuals or biennials. 

 Lenuna nearly as broad as long, awnless or with a very short awn. 



9. B. brizaeformis. 

 Lemma much longer than broad, conspicuously awned. 

 Lemma and glumes glabrous. 



Awn much shorter than the lemma, nearly erect. 



Sheaths glabrous. 10. B. secalinus. 



Sheaths densely pubescent. 11. B. racemosus. 



