506 THE GRASS FAMILY. 



Awns to all the glumes 12. POLYPOOOB. 



Awns (often very small) to the flowering glume only, cr none. Outer glumes 



pointed but not awned 22 



Awns jointed, with a tuft of hairs at the JoinU .... 17. AIRA. 



Awns not jointed 23 



Outer glumes swollen and very shining at the base . . 14. GASTRIDIUM. 



Outer glumes not enlarged at the base 13. AOROSTIS. 



SpikeleU all sessile, in a simple spike (branched only in accidental 



luxuriant specimens) 28 



Spikelets single or clustered, in a loose and spreading or close and spike-like 



panicle 26 



Awns to some or all the glumes .31 



SpikeleU entirely without awns 40 



Spikelets 3- or more flowered, sessile in a single spike. 



( Two spikelets to each tooth of the spike 25. ELYMUS. 



26 < Spikelets all solitary . 27 



( SpikeleU clustered along the axis of the spike 41 



97 / SpikeleU with their sides to the main axis of the spike 28 



"' \ SpikeleU with one edge (the backs of the glumes) to the main axis . . .29 



( Outer glumes nearly equal. SpikeleU very closely sessile, or indented. 

 28-^ 27. AOROPYRUM. 



( Outer glumes unequal. Spikelets almost sessile . . .29. BRACHYPODIUM. 



{One empty glume at the base of each spikelet (except the terminal one). 

 SpikeleU indented in the axis 28. LOLIUM. 

 Two empty glumes at the base of each spikelet SpikeleU almost sessile . 30 

 I Perennial. SpikeleU 6 lines long or more .... FKSTtiCA elatior. 

 \ Annual. SpikeleU not above 8 lines long POA loliaeea. 



Spikelets 2- or more flowered, panicled, owned. 



.,, / Flowering glumes all awned 32 



*" ( SpikeleU with 1 awnless perfect flower, and 1 awned male flower . . .38 

 fAwns inserted on the back of the flowering glumes, near or brlow the centre. 



Ilairs on the axis between the flowers short 31 



82 Awns terminal. Flowering glumes surrounded by hairs longer than them- 

 selves 42. AKUNDO. 



Awns terminal or nearly so. Azis of the spikelet without hairs . . .35 



SpikeleU 2-flowered 34 



SpikeleU 3- or more flowered 18. AVKNA. 



SpikeleU 2 lines or less. Awn fine, scarcely protruding beyond the glumes. 



17. AIRA. 

 SpikeleU 3 or 4 lines long. Awn exscrted. One of the flowers male only. 



19. ARRHENATHKRUM. 

 f Awns quite or very nearly terminal, sometimes reduced to a very short point 36 

 35 < Membranous edges of the glumes projecting in 2 points beyond the bnse of the 



wns . .... 80. BROMUS. 



34 



. ( Spikelets crc 

 30 \ Panicle loose 



vded in a close spike or dense clusters 



.nose or contracted Into a long one-sided spike 

 / Outer spikelet of each cluster consisting of empty glumes only 



' All the spikelets containing flowers 



One terminal awnless flower and a lower male flower awned 



37 

 81. FESTCCA. 



33. CYNOSURU8. 



32. DACTTLIS. 

 8. PANICUM. 



Awnless Hower the lowest, with a terminal awned male one 

 Outer glumes 2 to 3 lines, completely enclosing the flowers and their awns. 

 an 20. IIOLCUS. 



Outer glumes 8 to 6 lines, the flowers or at least their awns protruding. 



19. ARRHKNATHKRUH. 



Spikelets 2- or more flowered, aimless, panieled or in a compound spike. 



EikcIcU 2 or 3 together to each notch of an apparently simple spike. 

 25. ELYMUS. 

 ikelets sessile, in close clusters in an apparently simple spike or spike-like 

 panicle 41 

 ikeleU more or less stalked, in a loose or contracted panicle. . . .48 

 ( A small bract at the base of the spikelets or clusters .. . 41. SESLRRIA. 

 41 { Outer sptkelet of each cluster consisting of empty glumes. . 33. CYNOSURU8. 

 ( SpikeleU all containing flower* without bracts at the base of the cluaten . 42 



