ParRT 2, 1912] POACEAE 
mm. long; blades flat or some- 
times folded. 
Spikelets 3-4 mm. long; racemes 
usually long-exserted from the 
apex of the spathes, the com- 
mon peduncle sometimes con- 
siderably exposed. 
Tall stout grasses; inflorescence 
much branched. 8. 
Low slender grasses; inflores- 
cence simple or but little 
branched. 
Basal hairs shorter than the 
spikelets, which are 3.5-4 
mm. long, narrowly lanceo- 
late, acuminate. 9. 
Basal hairs much longer than 
the spikelets, which are 
3-3.5 mm. long, elliptic, ob- 
tuse, or merely acutish. 10. 
Spikelets 4.5-5 mm. long. 
Stems slender, sparingly 
branched; leaf-blades 3 mm. 
wide or less; awns 1.5-2 cm. 
long. 
Stems stout, much branched 
above; leaf-blades 4-7 mm. 
wide ; awns 6-10 mm. long. 12. 
Racemes in 4’s or 5's. 
Sessile spikelet 3-4 mm. long, the awn 
about 1.5 cm. long; racemes often en- 
tirely exserted from the spathe, ex- 
posing the peduncle. 13. 
Sessile spikelet 4.5-5 mm. long, the awn 
2-2.5 cm. long ; racemes, at least below, 
included in the spathes. 14. 
Sheaths at the summit or upper part of the stem 
much enlarged. 
Only some of the flowering stems with the en- 
larged sheaths, the lower sheaths much ex- 
ceeding the internodes. 15. 
All the flowering stems with such sheaths, 
the lower ones shorter than the internodes. 
Racemes of 4-6 internodes. 17 
Sessile spikelet with the intercarinal space of the first 
scale 2-nerved; anthers 3 mm. long. 
Sessile spikelet 6.5-7 mm. long, the awn perfect, geniculate, 
with a long well-defined spiral column as long as the 
subula; pedicellate spikelet 5-6 mm. long. 
Stamens 3. 
Sessile spikelet awnless, or rarely with a very short imperfect 
awn. G 
Branches of the inflorescence much divided, forming dense 
corymbiform masses at the apex of the stem ; pedicellate 
spikelet often staminate. 20. 
Branches of the inflorescence simple or a little branched, 
forming a lax narrow inflorescence. 21. 
Sessile spikelet awned, the awn perfect, with a manifest 
spiral column. 
First scale of the sessile spikelet with the intercarinal 
space appressed-hispid, rather thin, usually depressed ; 
leaf-sheaths sometimes pubescent. 
Intercarinal space nerveless, or sometimes with 1 or 2 
short nerves; terminal hairs of the internodes about 
twice their length. 22. 
Intercarinal space with 2 or 3 nerves running the entire 
length of the scale; terminal hairs of the internodes 
about equaling them in length. 23. 
First scale of the sessile spikelet with the intercarinal 
space glabrous and shining, flat, firm; leaf-sheaths gla- 
brous and, with their blades, glaucous. 
Pedicellate spikelet staminate, of 3 or 4 scales, equaling or exceed- 
ing the sessile spikelet. 
Sessile spikelet awnless, 6 mm. long or less, 25. 
Sessile spikelet awned, usually 7 mm. long or more. 
Internodes copiously pubescent with long hairs, 
Awn perfect, with a well-defined column; stems tufted, or 
sometimes with short rootstocks, 
BN 
A. 
peel 
. floridanus. 
. Subtenuis. 
Nashianus. 
. Tracyt. 
. Bakeri. 
. Liebmannt. 
. Mohrii. 
. campyloracheus. 
. LElliottii. 
. bvachystachyus, 
. arcialus, 
. Pringle. 
. btcornis, 
. deucostachyus. 
. lernarius, 
. Cabanistt, 
. Scribnerianus, 
. Bourgaei. 
