LXXXIX. GRAMINEjE. 505 



of food for man, in the shape of grain, and for cattle as constituting the 

 chief portion of meadows and pastures. 



, / Spikelets 1-flowered 2 



\ Spikelets containing 2 or more flowers 24 



C Spikelets arranged along one side of a slender, simple, linear spike . . 3 



„ I Spikelets arranged along one side of the simple, linear branches of the panicle 5 

 J Spikelets arranged in a close, cylindrical or ovate spike or spike-like panicle . 7 

 1^ Spikelets arranged in a loose, branching panicle 16 



Spikelets 1-flowered, in one-sided linear spikes. 



( Glume 1 only, ending in a fine point, and enclosing the palea and flower. 

 d\ 24. Narbus. 

 ( Two outer empty glumes and a flowering one 4 



{Outer glumes 1 line long, thin, and obtuse. Axis not jointed . 10. Mibora. 

 Outer glumes 2 lines long, stiff, and strongly ribbed. Axis jointed. 

 23. Lepturus. 

 f. f Spikelets in pairs or clusters along the branches ... 3. Panicum. 

 \ Spikelets single along the branches 6 



(Spikelets half an inch long, laterally flattened. Glumes all strongly keeled, 

 erect 22. Spartina. 



Spikelets about a line long. Outer glumes spreading . . 21. Cynodon. 

 Spikelets 1-flowered, in a dense spike or spike-like panicle. 

 h / Outer glumes without awns. Flowering glumes with or without awns . . 8 



\ All the glumes awned 13 



f Only 2 nearly equal empty glumes enclosing the flower 9 



I An additional small empty glume outside the 2 equal ones . 3. PANICUM. 

 I Two additional small, awned, empty glumes, withinside the two equal ones. 



5. Anthoxanthum. 

 ( Outer glumes swollen and shining at the base. Spikelets rather small. 

 9-j 14. Gastridium. 



( Outer glumes keeled or boat-shaped 10 



( A tuft of hairs at the base of the flower, within the outer glume. Reed-like 



10 \ grass with a very long spike 15. PSAMMA. 



( No tuft of hairs outside the flower within the outer glumes. Spikelets flat . 11 

 /Flowering glume with a fine awn on its back (sometimes shorter than the 



11 -J outer glume). No inner palea 9. Alopecurus. 



( Flowering glumes without awns. Inner palea present 12 



12 f Keel of the outer glumes expanded into a flat wing ... 6. Phalaris. 



\ Keel of the outer glumes not winged 8. Phleum. 



f Spikelets 3 together on each tooth of the simple, close, cylindrical spikes, 



.jo J 1 or 2 of each cluster reduced to a pair of empty glumes . . 26. Hordeum. 

 I Spikelets small and numerous, in a close spike-like panicle, all containing 

 V. flowers 14 



14 r Flowering glumes without awns 8. Phleum. 



\ Flowering glumes awned as well as the outer ones 15 



..r /Spike ovate, with long softly silky hairs 11. Lagurus. 



\ Spike cylindrical or branched, not hairy 12. Polypogon. 



Spikelets 1-flowered, in a loose panicle. 



lfi / Spikelets ovate, obtuse or scarcely acute 17 



\ Spikelets lanceolate, pointed 19 



( Spikelets very flat, consisting of only 2 glumes, both keeled . . 1. Leersia. 



17 ■] Spikelets scarcely flattened. Two outer empty glumes about the size of the 



( flowering one IS 



f Spikelets rather large, containing within the outer glumes, besides the flower, 



1S J a small, wedge-shaped, terminal glume or rudimentary flower 3S. Melioa. 

 J Spikelets small, containing nothing besides the flower within tlie outer 



V glumes 2. Milium. 



( Small tufts of hairs or hairy appendages at the base of the flower within the 



19 -j outer glumes 20 



( No hairs or hairy appendage at the base of the flower within the outer glumes 21 

 f No awns. A small hairy appendage at the base of the flower on each side. 



20 J 7. DlGRAPHIS. 



j Flowering glume with a short fine awn. A tuft of hairs at the base of the 

 t flowers 16. Calamagrostis. 



