506 THE GRASS FAMILY. 
Awns to all the Sted . 12. POLYPOGON. 
af Awns (often very small) to the flowering Sri only, or none. Mg: glumes 
| pointed but not awned : A : 2 22 
29 { Awns jointed, with a tuft of hairs ‘at the joints : : : | 1% AIBA 
Awns not jointed ' ‘ . . 23 
23 Outer glumes swollen and ver y shining at the base. p 14, G-ASTRIDIUM. 
Outer elumes not enlarged at the base . 13. AGROSTIS. 
( Spikelets all sessile, in a simple ‘spike (branched only in accidental 
O4 luxuriant specimens) . 
Spikelets single or clustered, ina loose ‘and ‘spreading or close and spike-like 
panicle . : : ; : é : ‘ . 
25 f Awns to some or all the olumes : , : : . : : : : "31 
\ Spikelets entirely without awns . ‘ : ; é j : 3 : . 40 
Spikelets 3- or more flowered, sessile in a single spike. 
( Two spikelets to each tooth of the spike. P ; ‘ : 25. ELYMUS. 
26 Spikelets all solitary é : ‘ : : } F : 
{ Spikelets clustered along the axis of the spike : ¢ é ; , “val > 
on fs Spikelets with their sides to the main axis of the spike : ‘ ‘ . 28 
| Spikelets with one edge (the backs of the glumes) to the main axis . ‘ ~ 29 
( Outer glumes nearly equal. Spikelets very closely sessile, or indented. 
8- 27. AGROPYRUM. 
( 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. Ps 28. LOLIUM. 
( Two empty glumes at the base of each spikelet. Spikelets. almost sessile 30 
30) Perennial. Spikelets 6 lines long or more . 7 ; : FESTUCA elation. 
Annual. Spikelets not above 3 lineslong . : ‘ : ; POA loliacea. 
Spikelets 2- or more flowered, panicled, awned. 
o, { Flowering glumes all awned . : : Bay: 
”” \ Spikelets with 1 awnless perfect flower, and 1 awned male flower. A 4 08 
Awns inserted on the back of the flowering glumes, near or below the centre. 
Hairs on the axis between the flowers short 
— 
32 Awns terminal. Flowering glumes surrounded by hairs longer than them- 
| selves. : 42, ARUNDO. 
Awns terminal or nearly so. Axis of the spikelet without hairs. 7 . 35 
93 f Spikelets 2-flowered : : : ‘ : : ; : 34 
\ Spikelets 3- or more flowered | 18. "AVENA. 
Spikelets 2 lines or less. Awn fine, scarcely protruding beyond the glumes. 
34 “17, ATRA. 
Spikelets 3 or 4 lines long. Awn exserted. One of the flowers male only. 
19. ARRHENATHERUM. 
=| Awns quite or very nearly terminal, sometimes reduced to a very short point 36 
Membranous edges of the glumes projecting in 2 points berona the base of the 
awns. : : 30. BROMUS. 
26 Les: crowded in a close spike or dense clusters . ; : 37 
Panicle loose or contracted into a long one-sided spike : H 31. FESTUCA. 
37 { Outer spikelet of each cluster consisting of empty glumes only 33. CYNOSURUS. 
All the spikelets containing flowers : . - on, DACIITE: 
38 { One terminal awnless flower and a lower male flower awned_ . 3. PANICUM. 
Awnless flower the lowest, with a terminal awned male one . « 39 
Outer glumes 2 to 3 lines, completely enclosing the flowers and their awns. 
39 20. HOLOUS. 
Outer glumes 3 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. 
40< Spikelets sessile, in close clusters in an apparently simple ee or eee 
panicle . ‘ . 41 
Spikelets more or less stalked, in a loose or contracted panicle . 43 — 
( A small bract at the base of the spikelets or clusters | 41, SESLERIA. 
41- Outer spikelet of each cluster consisting of empty glumes. . 383. CYNOSURUS. | 
( Spikelets all containing flowers without bracts at the base of the clusters . 42 — 
