ventrally.
Spikelets are binate, one sessile and one pedicelled; the pedicelled
spikelets are dissimilar from the sessile and both usually 2-flowered.
The sessile spikelets have four glumes. The first glume is coriaceous,
oblong or lanceolate, convex more or less, marginally winged above the
middle, truncate or two-cuspidate at the apex and awnless. The second
glume is as long as the first, coriaceous, concave, acute or obtuse,
awned or not. The third glume is hyaline, deeply cleft into two lobes
with an awn in the cleft, and 3-nerved, paleate; palea is
linear-lanceolate enclosing either stamens and ovary or ovary alone.
Lodicules are cuneate or quadrate.

KEY TO SPECIES.

Racemes two or three; the first glume of the
sessile spikelet dorsally flat, not
channelled or depressed along the middle line.

Margin of the first glume of the sessile
spikelet incurved narrowly from the base to
the apex.

First glume of sessile spikelets with
nodulose margins. 1. I. aristatum.

First glume of sessile spikelets closely
transversely ribbed. 2. I. rugosum.

First glume of the sessile spikelet
translucent, bicuspidate at the tip and
with smooth margins. 3. I. pilosum.

Margin of the first glume of the sessile
spikelet broadly incurved from below the
middle.

First glume of the sessile spikelet with
smooth margins, callus bearded. 4. I. ciliare.

Raceme solitary; the first glume of the sessile
spikelet deeply grooved at the back along the
middle line. 5. I. laxum.

=Ischaemum aristatum, _L._=

This is a perennial grass, with fairly stout, erect or somewhat
decumbent, simple or branched, glabrous, leafy stems, 1 to 4 feet high.

The _leaf-sheath_ is loose, glabrous and auricled. The _ligule_ is a
distinct membrane, broad or narrow. _Nodes_ are glabrous.

The _leaf-blade_ is linear-lanceolate, flat, acuminate, narrowed towards
the base which may be acute, subcordate or rarely even petiolate,
glabrous or sparsely hairy above and glaucous beneath, 4 to 10 inches
long and 1/4 to 1 inch broad.

The _inflorescence_ consists of one or two, erect, stout or slender,
fragile racemes, 1 to 5 inches long.

[Illustration: Fig. 130.--Ischaemum aristatum.

1. A portion of the raceme showing the joints, sessile and pedicel