488 
32. Sporobolus. Floral glume awnless, loosely enveloping the oblong or spherical 
grain. 
33. Muhlenbergia. Floral glume awned or at least mucronate, closely envelop- 
ing the narrow grain. 
34. Bpicampes. Like the preceding: panicle dense, long and narrow, 
* * * Ploral glume obtuse, denticulate, with a very short dorsal awn or awnless; 
empty glumes exceeding the small floret. 
35. Agrostis. Floral glume obtuse, 5-nerved: awn very short or wanting. 
36. Gastridium. Floral glume with a slender dorsal awn, exserted beyond the 
long empty glumes. 
Subtribe 3. Panicles contracted to narrow cylindrical spikes: floral glume dor- 
sally awned or awnless, not enveloping the grain,—Phleoidea. 
37. Lycurus. Empty glumes shorter than the floret, awned. 
38. Alopecurus. Empty glumes exceeding the floret, awnless, 
Tribe VIII. Spikelets 2 to many-flowered, paniculate: upper floret imperfect: 
floral glume 2-toothed, with a bent awn in the sinus.—-AVENE.. 
39, Trisetum. Floral glume prominently 2-toothed: panicles open, usually nar- 
row. 
Tribe X. Spikes 2 to many-flowered, the upper floret usually imperfect: empty 
glumes always present awnless; floral glume with a straight awn or awnless: palet 
2-keeled.—FESTUCEE, 
* Floral glume cleft into 3 or more awned lobes at the apex or awned between the 
numerous lobes, 
+ Awns 7 or more. 
50. Pappophorum. Spikelets urn-shaped: panicles narrow, 
51. Cottea. Spikelets compressed, cuneate: panicles spreading. 
+ + Awns 3. 
52, Cathesticum. Spikelets small in cuneate clusters: perfect florets 2 or 3. 
46. Bouteloua. Spikelets in cuneate clusters in racemes: perfect floret only 1, 
53. Scleropogon. Spikelets rather large, di@cious; staminate form awnless. 
** Floral glume entire, dentate or 3-cleft, awnless or 1-awned in Festuca. 
+ Rachilla or floral glume bearing long hairs enveloping the florets. 
56. Arundo, Hairs on the glumes only. 
57. Phragmites. Hairs on the rachilla only. 
«. + Rachilla and glume naked or with hairs much shorter than the florets (except 
the narrow web at the base of the floret in Poa). 
++ Spikelets in sessile clusters, half concealed among the floral leaves, 
= Spikelets unisexual, usually diwcious. 
49, Bulbilis. Spikelets 2 or 3 together in short spikes: empty glumes thin. 
54. Monanthochle. Spikelets solitary: empty glumes coriaceous and rigid like 
the upper leaves. 
= = Spikelets perfect. 
55. Munroa. Floral glume mucronate, slightly pubescent, 
