Part 1, 1909] POACEAE 
Spikelets homogamous, or rarely the pedicellate one pistillate; fertile 
flowering scales usually awned, sometimes awnless. 
Rachis of the racemes continuous. 
Racemes in a narrow spike-like panicle; spikelets awnless. 
Rachis of the racemes articulate. 
Spikelets in pairs at each node of the rachis. 
Spikelets 1-flowered ; racemes in a panicle, the axis elongate. 
Spikelets awnless. 
Pedicellate spikelet perfect; panicle loose and open, the 
pubescence white. 11. 
Pedicellate spikelet pistillate ; panicle dense and spike- 
like, the pubescence golden-brown. 12 
Spikelets 2-flowered; racemes 2-many, digitate or approximate 
on a short axis. 
Spikelets heterogamous, the sessile perfect, the pedicellate staminate, 
empty, or wanting; if both spikelets are pedicellate, the one with 
the shorter pedicel is staminate, the one with the longer pedicel 
perfect. 
Spikelets 2-flowered. 
Pedicellate spikelets developed, bearing flowers. 15 
Pedicellate spikelets rudimentary, or wanting, and the pedicel only 
present. 
Spikelets 1-flowered. 
Spikelets all pedicellate ; axis of the racemes obscurely articulate. 17. 
Spikelets sessile and pedicellate ; axis of the racemes evidently 
articulate. 
Bs empty scale balsam-bearing; raceme single; spikelets awn- 
ess. 
First empty scale not balsam-bearing ; racemes when single with 
the sessile spikelets usually awned. 
No false whorl of staminate or empty spikelets at the base of 
the racemes; several pairs of staminate or empty spike- 
lets may be present, but never in whorls. 
Fourth or fertile scale awned on the back, often near the 
base ; leaf-blades cordate at the base. 19. 
Fourth or fertile scale with the awn terminal or arising 
from between the teeth, or sometimes awnless; leaf- 
blades not cordate. 
Inflorescence simple or compound, made up of 1 or 
more racemes which are sessile or on very short 
pedunicles. 
Sessile spikelets not cylindric. 
Spikelets strongly laterally compressed, the second 
scale long-awned ; intercarinal space of the first 
scale of the sessile spikelet narrow. 20. 
Spikelets dorsally compressed, the second scale 
awnless or nearly so; intercarinal space of 
the first scale of the sessile spikelet broad, flat 
or nearly so, or depressed. 
Raceme single, the internodes of the rachis and 
the pedicels clavate, spongy, usually stout, 
when separated with a deep cup-shaped 
depression at the apex which has a scarious 
hyaline entire or toothed margin ; pairs of 
spikelets all alike. ai. 
Racemes not single, or very rarely so, the rachis 
internodes and pedicels filiform or flat and 
linear, not spongy, sometimes thickened 
at the apex, never clavate, not appendaged 
at the apex; lower pairs of spikelets in 1 
or all of the racemes sometimes different 
from those above in sex, shape or awns. 
Internodes of the rachis and pedicels fili- 
form, sometimes stouter and convex on 
the back, not sulcate and furnished with a 
median hyaline line ; racemes arranged in 
pairs, or digitately in 5’s or less, sessile or 
83 
i 9. IMPERATA. 
Racemes in an open usually flabellate panicle; spikelets awned. 10. 
MISCANTHUS, 
SACCHARUM. 
. . ERIOCHRYSIS. 
Spikelets awned. 13. 
ERIANTHUS. 
; : 15. IscHAEMUM. 
Spikelets in 3’s at each node of the rachis. 14. 
POLYTRIAS. 
. ISCHAEMUM., 
16. EREMOCHLOA. 
TRACHYPOGON. 
18. ELYONURUS. 
ARTHRAXON. 
DIECTOMIs. 
SCHIZACHYRIUM. 
- only i pedunculate. 22. ANDROPOGON. 
Internodes of the rachis and pedicels flat, 
linear, the margins much thickened, the 
median portion hyaline or diaphanous ; 
racemes usually numerous, subflabellate 
or on an elongated axis, all more or less 
pedunculate. 23. AMPHILOPHIS. 
Sessile pistillate or perfect spikelets cylindric, 
markedly different from the pedicellate ones. 24, HETEROPOGON. 
