PIPER— FLORA OF THE STATE OF WASHINGTON. 129 



Dioecious, seashore plant; spikelets 10 to 15 mm. 



long 3. P. macrantha. 



Perfect; spikelets 4 to 5 mm. long 4. P. pratensis. 



Lemma not webbed. 



Low seashore plant with narrow involute leaves and 



small panicle 5. P. conjinis. 



Taller grasses, not maritime, with flat or folded 

 leaves. 



Florets loose; ligule very short, ciliate; lat- 

 eral nerves of lemma prominent 6. P. nervosa. 



Florets close; ligide rather long, not ciliate; 



lateral nerves of lemma not prominent ...... 7. P. olneyae. 



Plants tufted, without rootstocks. 



Lateral nerves of lemmas prominent ; web present 8. P. trivialis. 



Lateral nerves of lemmas not prominent. 

 Web present at base of lemma. 



Leaves flat or folded, not soft and flaccid. 



Panicle short, pyramidal; spikelets 6 to 7 mm. 



long; low alpine plant 9. P. arctica. 



Panicle ample, spreading; spikelets 3 to 4 mm. 



long 10. P. triflora. 



Leaves flat, rather short, soft and flaccid. 



Panicle lax, spreading; spikelets 5 to 6 mm. 



long; florets not early deciduous 11. P. leptocorna. 



Panicle narrow, the rays usually erect; florets 

 early deciduous. 



Lemma glabrous, or nearly so 12. P. holanderi. 



Lemma puljescent 13. P. howellii. 



Web absent, no tuft of hairs at base of lemma. 

 Nerves of the lemma pilose below. 



Alpine plant; leaf blades flat, green, broad 14. P. alpinn. 



Maritime plant; leaf blades narrow or folded, 



glaucescent 15. P. pachypholis. 



Nerves of lemma not pilose. 



Stems coarse, 60 to 100 cm. high. 



Leaves flat, rarely involute, green or rarely 

 glaucescent; panicles ample. 

 Ligules long. 

 % Panicle compact, lemmas sca- 

 brous 16. P. canbyi. 



Panicle looser; lemmas pubes- 

 cent 17. P. leckenbyi. 



f Ligules short; panicle loose 18. P. ampla. 



Leaves narrow, involute, pale; panicles 

 narrow, erect. 



Ligules short 19. P. hrach yglossa. 



Ligules long 20. P. neradensis. 



Stems not coarse nor tall, usually under 60 cm. 

 in height. 



Leaves very narrow, filiform and involute. 

 Panicles loose. 



Florets distant; ligule short. . . . 28. P. idahoen.iis. 



Florets close; ligule long 29. P. cajnllarifolia. 



29418' -06 M 9 



