named _echinoides_. This differs from
the type in the following respects--the inner bristles are united very
much above the base and much thickened and stiffer than in the type.
(See fig. 116-3)

10. Cenchrus, _L._

The inflorescences are spike-like racemes, consisting of involucellate
clusters of shortly pedicelled spikelets jointed on a simple rachis. The
involucel consists of hardened spike-like bristles connate at the base
into a short coriaceous cup, which is surrounded by erect or squarrose
bristles. Spikelets one to three in each involucel, persistent, 1- to
2-flowered, with three or four glumes. The first glume is very small or
absent. The second and the third glumes are subequal 5- to 7-nerved. The
third glume is longer than the second with male flower or not, paleate.
The fourth glume is coriaceous, with a bisexual or female flower.
Lodicules are two. Stamens are three. Styles are long, free or connate
below. Grain is broad, oblong and compressed.

KEY TO THE SPECIES

Base of involucel rounded; inner bristles
shorter, erect, not ciliate 1. C. biflorus.

Base of involucel turbinate, inner bristles
longer, spreading and spinescent, ciliate
at base 2. C. catharticus.

=Cenchrus biflorus, _Roxb._=

This is an annual with erect simple stems, 6 to 24 inches long.

The _leaf-sheath_ is glabrous or nearly so, with hairs at the mouth.

The _leaf-blade_ is linear-lanceolate, finely acuminate, glabrous or
hairy, 3 to 10 inches long and 1/8 to 3/8 inch broad.

The _inflorescence_ is a solitary cylindric raceme of involucels, 2 to 4
inches long, enclosed in the uppermost leaf-sheath; the _rachis_ is
flexuous, angular and smooth. _Involucels_ usually with two, rarely
three spikelets, loosely imbricate, rounded at the base; the inner
bristles are erect, dorsally flat, subulate-lanceolate, puberulous and
with thickened margins, about 1/8 inch long. The outer are shorter than
the inner, glabrous, erect or subsquarrose and as long as the sessile
spikelets.

The _spikelets_ are about 1/6 inch long, sub-globose, with four
_glumes_. The _first glume_ is about 1/10 inch long, ovate-acuminate,
very thin, hyaline, nerveless or rarely 1-nerved. The _second glume_ is
broadly ovate, 1/6 inch long, hyaline, acute, 1-nerved. The _third
glume_ is slightly longer than the second, oblong-ovate, apiculate,
5-nerved and paleate; _palea_ 1/8 inch obtuse. The _f