PIPER—FLORA OF THE 
Dioecious, seashore plant; spikelets 10 to 15 mm. 
long....----- 2222-22-22 ee ee ee ee ee ee ee eee 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..............----2------------- 5. P. confinis. 
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; ligule 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 4mm. 
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. leptocoma. 
Panicle narrow, the rays usually erect; florets 
early deciduous. 
Lemma glabrous, or nearly so.......---- 12. P. bolanderi. 
Lemma pubescent... ..-.-.-.-.--------- 13. P. howellit. 
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. alpina. 
Maritime plant; leaf blades narrow or folded, 
glaucescent..........----------+--------- 15. P. pachypholis. 
Nerves of lemma not pilose. 
Stems coarse, 60 to 100 em. 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. 
Ligules short; panicle loose seeeeee- 18. P. ampla. 
Leaves narrow, involute, pale; panicles 
narrow, erect. 
Ligules short...........----------- 19. P. brachyglossa. 
Ligules long..........-.----------- 20. P. nevadensis. 
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. idahoensis. 
Florets close; ligule long... - -- - 29. P. capillarifolia. 
29418- -06 m 
STATE OF WASHINGTON, 
129 
