PIPER — NORTH AMERICAN 3PEOIE8 OF FE8TXJ1 L 



Spikelete do1 at all hirsute. 



Spikelete with glumee only hirsute 



Spikelete with lemma only hirsute. 



Spikelete wholly hirsute. 

 Florets mostly 1 to 3 in each b pikelet; all the spiki 

 divaricate. 



Spikelete not at all pubescent. 



Spikelete with only the Lemma pubscent. 



Spikelete wholly pubescent 

 Branches of the narrow elongated panicle erect or appn 

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



Lemma aot ciliate. 



Lemma ciliate. 

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

 second. 



Lemma smooth <»r scabrous. 



Lemma pubescent. 



- 



8 fusa. 



■ 



5. grayi. 



7. microtia 

 twoodae. 



9. myuro8. 

 LO. megalura. 



1 1. bromoides. 

 irea. 



Subgenus Eufestu* \. Perennials, mostly tufted and never with scaly rootstocks; 

 stamens:'), protruding in anthesis; stigmas bilaterally plumose, the branches toothed. 

 Plants densely tutted, or with narrow and involute blade-, usually 

 both: lemma awnless or awned. 



Ligule short; collar and auricle- not conspicuously bristly, or 

 tomentoee. 

 Blades not falling away from the sheaths; palea obtuse or 

 bidentate at apex. 

 Innovations extravaginal; blades smooth; Bpikeleta 



usually more or less glaucous. L3. rubral 



Innovations intravaginal. 



Tufts easily separable; blades closely involute: 

 pulvilli none or faintly developed. 



Awns longer than the membranous Lemmas; 



blade- soft, sulcate; ovary hispidulous at 



apex. 14. occidentalis. 



Awns not l< 'Hirer than the coriaceous lemmas: 



ovary glabrous. 



Blades various, but when hard the 



lemma awned. L5. ovina. 



Blades smooth, firm, rigid; lemma awn- 

 less. 16. 

 Tufts separable with difficulty; blades narrow, 

 loosely involute or flat; lemma thin; a pulvil- 

 lus at the base of each ray. 

 Lemma smooth, usually awnless. sometimes 



awn-pointed. 17. viridula. 



Lemma scabrous-puberulent, short-awned. 18. J><>ir,/!ii. 

 Blades at length falling away from the persisting sheaths; 

 palea notched at apex. 

 Panicle rays spreading; spikelete >hiniiiL r : culm and 



loosely involute green blades smooth or nearly bo. I' 1 , altaica. 

 Panicle ray- erect or becoming -<•: -pikelets dull: 

 culm and closely involute glaucescent blades usu- 

 ally very scabrous. 20. haUii. 

 Ligule short, ciliate; collar and auricle- tomentoee or bristly. 21. arutulata. 

 Ligule 4 to 9 mm. long, ecarious. 22. thurbt 



