PIPER JS'ORTH AMERICAN SPECIES OF FESTUCA. 



Spikelets not at all hirsute. 



Spikelets with glumes only hirsute. 



Spikelets with lemma only hirsute. 



Spikelets wholly hirsute. 

 Florets mostly 1 to 3 in each spikelet; all the spikelets 

 divaricate. 



Spikelets not at all pubescent. 



Spikelets with only the lemma pubscent. 



Spikelets wholly pubescent. 

 Branches of the narrow elongated panicle erect or appressed. 

 First glume one-third to one-half as long as the second. 



Lemma not ciliate. 



Lemma ciliate. 

 First glume two-thirds to three-fourths as long as the 

 second. 



Lemma smooth or scabrous. 



Lemma pubescent. 



2. pacifica. 



3. confusa. 



4. eriohpis. 



5. grayi. 



6. reflexa. 



7. microstachys. 



8. eastwoodae. 



9. myuros. 

 10. megalura. 



11. bromoides. 



12. sdurea. 



Subgenus Eufestuca. Perennials, mostly tufted and never with scaly rootstocks; 

 stamens 3, protruding in anthesis; stigmas bilaterally plumose, the branches toothed. 



Plants densely tufted, or with narrow and involute blades, usually 

 both; lemma awnless or awned. 

 Ligule short; collar and auricles not conspicuously bristly, or 

 tomentose. 



Blades not falling away from the sheaths; palea obtuse or 

 bidentate at apex. 

 Innovations extra vaginal; blades smooth; spikelets 



usually more or less glaucous. 13. rubra. 



Innovations intravaginal. 



Tufts easily separable; blades closely involute; 

 pulvilli none or faintly developed. 



Awns longer than the membranous lemmas; 

 blades soft, sulcate; ovary hispidulous at 

 apex. 14. occidentalis. 



Awns not longer than the coriaceous lemmas; 

 ovary glabrous. 



Blades various, but when hard the 



lemma awned. 15. ovina. 



Blades smooth, firm, rigid; lemma awn- 

 less. 16. rigescens. 

 Tufts separable with difficulty; blades narrow, 

 loosely involute or flat; lemma thin; a pul vil- 

 lus at the base of each ray. 

 Lemma smooth, usually awnless, sometimes 



awn-pointed. 17. ciridula. 



Lemma scabrous-puberulent, short-awned. 18. hov^ellii. 

 Blades at length falling away from the persisting sheaths ; 

 palea notched at apex. 

 Panicle rays spreading; spikelets shining; culm and 



loosely involute green blades smooth or nearly so. 19. altaica. 

 Panicle rays erect or becoming so; spikelets dull; 

 culm and closely involute glaucescent blades usu- 

 ally very scabrous. 20. halHi. 

 Ligule short, ciliate; collar and auricles tomentose or bristly. 21. aristidnta. 

 Ligule 4 to ^mm. long, scarious. 22. tliiirheri 



