113 



6. Fertile spikelets 2-3-fiowered, awnless; the sterile with numer- 

 ous awned or awn-pointed glumes 115. Cynosueus 



6. Fertile spikelets 1 -flowered, long-awned; the sterile with many 



obtuse glumes 116. Lamarckia 



7. Plants dioecious 8 



7. Plants not dioecious 11 



8 Spikelets solitary, concealed in the axils of the crowded, short, 

 and rigid leaves 90. Monanthochloe 



8. Spikelets in exserted panicles 9 



9. Flowering glumes 3-nerved, subulate, the midnerve extending 



into a fine awn. Tall reed-like grass 93. Gynerium 



9. Flowering glumes 5- to many-nerved, broad, ovate, or oblong, 

 awnless 10 



10. Flowering glumes many-nerved, coriaceous; spikelets few in 

 short, spike-like panicles 112. Distichlis 



10. Flowering glumes 5-nerved, herbaceous or chartaceous. 117. Poa 



11. Empty glumes 3 to 6 below the first flowering glume 12 



11. Empty glumes 2, or rarely only 1, below the first flowering 



glume 13 



12. Third and fourth glumes similar to the first and second, all awn- 



less. Tall grasses with strongly compressed spikelets. 



111. Uniola 



12. Third and fourth glumes very unlike the first and second, 



3-nerved and 3-awned. Low, desert grasses. 



96. Blepharidachne 



13. Rachilla or flowering glumes clothed with long hairs exceeding 



the glumes in length. Tall, reed-like grasses 14 



13. Rachilla or flowering glumes naked or with hairs shorter than 



the glumes 16 



14. Leaves narrow and very long, chiefly radical; culms solid. 



93. Gynerium 



14. Leaves broader, chiefly cauline; culms hollow 15 



15. Hairs on the rachilla only 95. Phragmites 



15. Hairs on the flowering glumes, the rachilla naked. 



94. Arundo 



16. Culms dichotomously branched; leaves crowded in dense 



fascicles at the nodes or ends of the branches. . 91. Munroa 



16. Culms not dichotomously branched; leaves not in dense 



fascicles 17 



15444— No. 20 8 



