504 THE GRASS FAMILY. 
12 § Keel of the outer glumes expanded into a flat wing . » Th 6. PHALARIS. 
Keel of the outer glumes not winged . 8. PHLEUM. 
Spikelets 3 together on each tooth of the simple, close, eylindrical spikea, lor 2 
13 of each cluster reduced to a pair of empty glumes. ° . HorpEum. 
a ie small and aa in a close spike-like panicle, al containing 
owers . : P . . . 
14 f Flowering glumes without awns ; F ° oe Puevm. 
Flowering glumes awned as well as the outer ones . . a ie p . 15 
1b ji Spike ovate, with long softly silky hairs ., ° ’ ° . 11. LaGurvs. 
Spike cylindrical or branched, nothairy . ‘ . . 12. PoLyPogon, 
Spikelets 1-flowered, in a loose panicle. 
16 fear ovate, obtuse or scarcely acute . , P ° . ‘ ° eit 
Spikelets lanceolate, pointed . . . 19 
{ Spikelets very flat, consisting of only 2 glumes, ‘oth keeled ; ae LEERSIA, 
17 
Spikelets scarcely flattened. Two outer empty glumes about the size of the 
flowering one ; 18 
Spikelets rather large, containing within the outer glumes, besides the flower, 
18 a small, wedge-shaped, terminal glume or rudimentary flower 38. Meuica. 
Spikelets ‘small, containing nothing besides the flower within the outer glumes, 
2. Mit1um. 
Small tufts of hairs or hairy appendages at the base of the flower within the 
19) outer glumes - 20 
No hairs or hairy appendage at the base of the flower within the outer glumes 21 
No awns. A small hairy appendage at the base of the flower on each side. 
20 7, DIGRAPHIS, 
Flowering glume with a short art awn, A si of hairs at the base of the 
flowers . : ; : . - 16, CALAMAGROSTIS. 
Awns to all the ‘glumes . : fei . 12, PotyPoeon. 
aif Avwns (often very small) to the flowering elume only, or none. mes glumes 
pointed but not awned : ° : 22 
99 fee jointed, with a tuft of hairs at the joints A ° ; : EL AS.0: To 
Awns not jointed 
93 5 Outer glumes swollen and very shining at the base . P . 14, Gasrripium, 
84 Onter glumes not enlarged at the base . 13. AGROSTIS, 
Spikelets all sessile, in a “nls spike (branched only i in accidental luxuriant 
9 4 specimens) . 
Onset peeks or clustered, ‘ina loose and spreading or close and spike- -like 
panicle . - : sas ase ; - P . : 
°5 oc to some or all the glumes ; : . ° . ° ° . oh an 
Spikelets entirely without awns . Seem ¢ Sch ° : Mae - 40 
Spikelets 3- or more flowered, sessile in a single spike, 
¢ Two spikelets toeachtooth of the spike . . . . -« 25. ELYMvs. 
26$ Spikelets all solitary : . A : - : ; x 
q Spikelets clustered along the axis ‘of the spike - ‘ ° : ° . . 41 
97 § Spikelets with their sides to the main axis of the spike . «> eee 
( Spikelets with one edge (the backs of the glumes) to the main axis . . 29 
a Outer glumes nearly equal. Spikelets very closely sessile, or indented. 
27. AGROPYRUM, 
U Outer glumes unequal. Spikelets almost sessile . . 29. BRACHYPODIUM. 
3 empty glume at the base of each ae (except the terminal one), 
29 
28 
Spikelets indented in the axis . . 28. Lotium. 
( Two empty glumes at the base of each spikelet. Spikelets almost sessile . 30 
30 Perennial. Spikelets 6 lines long or more : ; . Fxsruca elatior, 
{Annual Spikelets not above 3 lines long . : ; . . . Poa loliacea, 
Spikelets 2- or more flowered, panicled, awned. 
3] if Flowers glumes all awned . ° ° . 32 
Spikelets with 1 awnless perfect flower, and 1 awned male flower . . 38 
Awns inserted on the back of the flowering glumes, near or below the centre. 
j Hairs on the axis between the flowers short . 3 
32, Awns terminal. Flowering glumes surrounded by hairs longer than themselves, 
RUNDO 
| Awns terminal or nearly so, Axis of the spikelet without hairs . - » Bb 
83 { Spikelets 2-flowered : 5 . 5 : : Fel . 34 
Spikelets 3- or more flowered Co 8 
) 
| 
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