aa. 
bb. 
(12). 
Agrostis.—Glumx acute, the inferior 
one larger. Pale membranaceous. 
Calamagrostis.—Glume acute, the in- 
ferior one larger. Palez surrounded by 
silky hair at the base. 
Stipa.—Glumex acute, sometimes aris- 
tate. Palezx cartilaginous, the inferior 
one cylindrically involute. Awn strong, 
articulate at the base, persistent, de- 
veloped from the apex of the palea. 
Gastridium.—Glumez acute, very much 
compressed, ventricose at their base. 
Palesw membranaceous. 
Spikelets pedicillate, 2--flowered, the 
uppermost floret frequently rudimentary. 
Stigma aspergilliform, exserted below the 
apex of the floret. 
Phragmites.—8 pikelets o-flowered, 
lowermost floret ¢ or neuter, the other 
florets § and pilose. 
Hierochloa.—Spikelets 3-flowered, the 
two inferior ones ¢ and triandrous, the 
terminal one 8 and diandrous. 
Stigma plumose, exserted near the base of 
the floret. 
Arrhenatherum.—Spikelets 2-flowered; 
inferior floret %, aristate; superior 
floret %, awnless. 
