THE GRASS FAMILY. 



( Awns to all the glumes 12. PoLYPOGOS. 



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



( pointed but not awned 22 



22 f Awns jointed, with a tuft of hairs at the joints . . . .17. AIRA. 

 \Awnsnotjointed . . 23 



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

 \0uterglumesnotenlargedatthebase ,13. AQROSTIS. 



I Spikelets all sessile, in a simple spike (branched only in accidental 

 luxuriant specimens) 20 

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

 panicle 26 

 Awns to some or all the glumes 31 

 Spikelets 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 



( Spikelets clustered along the axis of the spike 41 



y, ( Spikelets with their sides to the main axis of the spike 28 



1 Spikelets with one edge (the backs of the glumes) to the main axis . . .29 



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

 28 -j 27. AGROPTRUM. 



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



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

 29-^ Spikelets indented in the axis 28. LOLIUM. 



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

 o ( / Perennial. Spikelets 6 lines long or more .... FESTUCA elatior. 



\AnnuaL Spikelets not above 3 lines long POA loliacea. 



Spikelets - or more flowered, panicled, awned. 



,, / Flowering glumes all awned 

 I Spikelets with 1 awnless pert 



i perfect flower, and 1 awned male flower . . .38 

 f Awns inserted on the back of the flowering glumes, near or below the centre. 



Hairs on the axis between the flowers short 33 



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

 selves . 42. ARUNDO. 



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



oo / Spikelets 2-flowered 34 



\ Spikelets 3- or more flowered 18. AVBNA. 



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

 o 4 J 17. AIRA. 



I Spikelets 3 or 4 lines long. Awn exserted. One of the flowers male only. 

 I 19. ARRIIENATHERUM. 



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



36 f Spikelets crowded in a close spike or dense clusters 37 



\ Panicle loose or contracted into a long one-sided spike . . 81. FESTUCA. 



37 



41 



Outer spikelet of each cluster consisting of empty glumes only 83. CYNOSURU3. 



All the spikelets containing flowers 82. DACTYLIS. 



One terminal awnless flower and a lower male flower awned . 8. PANIOUM. 

 Awnless flower the lowest, with a terminal awned male one . . . .39 

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



20. HOLOUS. 

 Outer glumes 8 to 5 lines, the flowers or at least their awns protruding. 



19. ARRHENATHERUM. 



Spikelets 2- or more flowered, awnless, panicled or in a compound spike, 



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



25. ELYMUS. 

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



panicle 41 



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

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



Outer spikelet of each cluster consisting of empty glumes . . 33. CYNOSURUS. 

 Spikelets all containing flowers without bracts at the 



le base of the clusters . 49 



